diff mbox

[8/9] arm64: KVM: implement lazy world switch for debug registers

Message ID 1399476054-21571-9-git-send-email-marc.zyngier@arm.com
State New
Headers show

Commit Message

Marc Zyngier May 7, 2014, 3:20 p.m. UTC
Implement switching of the debug registers. While the number
of registers is massive, CPUs usually don't implement them all
(A57 has 6 breakpoints and 4 watchpoints, which gives us a total
of 22 registers "only").

Also, we only save/restore them when MDSCR_EL1 has debug enabled,
or when we've flagged the debug registers as dirty. It means that
most of the time, we only save/restore MDSCR_EL1.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kernel/asm-offsets.c |   1 +
 arch/arm64/kvm/hyp.S            | 449 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 444 insertions(+), 6 deletions(-)

Comments

Anup Patel May 19, 2014, 8:38 a.m. UTC | #1
On 7 May 2014 20:50, Marc Zyngier <marc.zyngier@arm.com> wrote:
> Implement switching of the debug registers. While the number
> of registers is massive, CPUs usually don't implement them all
> (A57 has 6 breakpoints and 4 watchpoints, which gives us a total
> of 22 registers "only").
>
> Also, we only save/restore them when MDSCR_EL1 has debug enabled,
> or when we've flagged the debug registers as dirty. It means that
> most of the time, we only save/restore MDSCR_EL1.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm64/kernel/asm-offsets.c |   1 +
>  arch/arm64/kvm/hyp.S            | 449 +++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 444 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
> index 646f888..ae73a83 100644
> --- a/arch/arm64/kernel/asm-offsets.c
> +++ b/arch/arm64/kernel/asm-offsets.c
> @@ -120,6 +120,7 @@ int main(void)
>    DEFINE(VCPU_ESR_EL2,         offsetof(struct kvm_vcpu, arch.fault.esr_el2));
>    DEFINE(VCPU_FAR_EL2,         offsetof(struct kvm_vcpu, arch.fault.far_el2));
>    DEFINE(VCPU_HPFAR_EL2,       offsetof(struct kvm_vcpu, arch.fault.hpfar_el2));
> +  DEFINE(VCPU_DEBUG_FLAGS,     offsetof(struct kvm_vcpu, arch.debug_flags));
>    DEFINE(VCPU_HCR_EL2,         offsetof(struct kvm_vcpu, arch.hcr_el2));
>    DEFINE(VCPU_IRQ_LINES,       offsetof(struct kvm_vcpu, arch.irq_lines));
>    DEFINE(VCPU_HOST_CONTEXT,    offsetof(struct kvm_vcpu, arch.host_cpu_context));
> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
> index 2c56012..f9d5a1d 100644
> --- a/arch/arm64/kvm/hyp.S
> +++ b/arch/arm64/kvm/hyp.S
> @@ -21,6 +21,7 @@
>  #include <asm/assembler.h>
>  #include <asm/memory.h>
>  #include <asm/asm-offsets.h>
> +#include <asm/debug-monitors.h>
>  #include <asm/fpsimdmacros.h>
>  #include <asm/kvm.h>
>  #include <asm/kvm_asm.h>
> @@ -215,6 +216,7 @@ __kvm_hyp_code_start:
>         mrs     x22,    amair_el1
>         mrs     x23,    cntkctl_el1
>         mrs     x24,    par_el1
> +       mrs     x25,    mdscr_el1
>
>         stp     x4, x5, [x3]
>         stp     x6, x7, [x3, #16]
> @@ -226,7 +228,202 @@ __kvm_hyp_code_start:
>         stp     x18, x19, [x3, #112]
>         stp     x20, x21, [x3, #128]
>         stp     x22, x23, [x3, #144]
> -       str     x24, [x3, #160]
> +       stp     x24, x25, [x3, #160]
> +.endm
> +
> +.macro save_debug
> +       // x2: base address for cpu context
> +       // x3: tmp register
> +
> +       mrs     x26, id_aa64dfr0_el1
> +       ubfx    x24, x26, #12, #4       // Extract BRPs
> +       ubfx    x25, x26, #20, #4       // Extract WRPs
> +       mov     w26, #15
> +       sub     w24, w26, w24           // How many BPs to skip
> +       sub     w25, w26, w25           // How many WPs to skip
> +
> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
> +
> +       adr     x26, 1f
> +       add     x26, x26, x24, lsl #2
> +       br      x26
> +1:
> +       mrs     x20, dbgbcr15_el1
> +       mrs     x19, dbgbcr14_el1
> +       mrs     x18, dbgbcr13_el1
> +       mrs     x17, dbgbcr12_el1
> +       mrs     x16, dbgbcr11_el1
> +       mrs     x15, dbgbcr10_el1
> +       mrs     x14, dbgbcr9_el1
> +       mrs     x13, dbgbcr8_el1
> +       mrs     x12, dbgbcr7_el1
> +       mrs     x11, dbgbcr6_el1
> +       mrs     x10, dbgbcr5_el1
> +       mrs     x9, dbgbcr4_el1
> +       mrs     x8, dbgbcr3_el1
> +       mrs     x7, dbgbcr2_el1
> +       mrs     x6, dbgbcr1_el1
> +       mrs     x5, dbgbcr0_el1
> +
> +       adr     x26, 1f
> +       add     x26, x26, x24, lsl #2
> +       br      x26
> +
> +1:
> +       str     x20, [x3, #(15 * 8)]
> +       str     x19, [x3, #(14 * 8)]
> +       str     x18, [x3, #(13 * 8)]
> +       str     x17, [x3, #(12 * 8)]
> +       str     x16, [x3, #(11 * 8)]
> +       str     x15, [x3, #(10 * 8)]
> +       str     x14, [x3, #(9 * 8)]
> +       str     x13, [x3, #(8 * 8)]
> +       str     x12, [x3, #(7 * 8)]
> +       str     x11, [x3, #(6 * 8)]
> +       str     x10, [x3, #(5 * 8)]
> +       str     x9, [x3, #(4 * 8)]
> +       str     x8, [x3, #(3 * 8)]
> +       str     x7, [x3, #(2 * 8)]
> +       str     x6, [x3, #(1 * 8)]
> +       str     x5, [x3, #(0 * 8)]
> +
> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
> +
> +       adr     x26, 1f
> +       add     x26, x26, x24, lsl #2
> +       br      x26
> +1:
> +       mrs     x20, dbgbvr15_el1
> +       mrs     x19, dbgbvr14_el1
> +       mrs     x18, dbgbvr13_el1
> +       mrs     x17, dbgbvr12_el1
> +       mrs     x16, dbgbvr11_el1
> +       mrs     x15, dbgbvr10_el1
> +       mrs     x14, dbgbvr9_el1
> +       mrs     x13, dbgbvr8_el1
> +       mrs     x12, dbgbvr7_el1
> +       mrs     x11, dbgbvr6_el1
> +       mrs     x10, dbgbvr5_el1
> +       mrs     x9, dbgbvr4_el1
> +       mrs     x8, dbgbvr3_el1
> +       mrs     x7, dbgbvr2_el1
> +       mrs     x6, dbgbvr1_el1
> +       mrs     x5, dbgbvr0_el1
> +
> +       adr     x26, 1f
> +       add     x26, x26, x24, lsl #2
> +       br      x26
> +
> +1:
> +       str     x20, [x3, #(15 * 8)]
> +       str     x19, [x3, #(14 * 8)]
> +       str     x18, [x3, #(13 * 8)]
> +       str     x17, [x3, #(12 * 8)]
> +       str     x16, [x3, #(11 * 8)]
> +       str     x15, [x3, #(10 * 8)]
> +       str     x14, [x3, #(9 * 8)]
> +       str     x13, [x3, #(8 * 8)]
> +       str     x12, [x3, #(7 * 8)]
> +       str     x11, [x3, #(6 * 8)]
> +       str     x10, [x3, #(5 * 8)]
> +       str     x9, [x3, #(4 * 8)]
> +       str     x8, [x3, #(3 * 8)]
> +       str     x7, [x3, #(2 * 8)]
> +       str     x6, [x3, #(1 * 8)]
> +       str     x5, [x3, #(0 * 8)]
> +
> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
> +
> +       adr     x26, 1f
> +       add     x26, x26, x25, lsl #2
> +       br      x26
> +1:
> +       mrs     x20, dbgwcr15_el1
> +       mrs     x19, dbgwcr14_el1
> +       mrs     x18, dbgwcr13_el1
> +       mrs     x17, dbgwcr12_el1
> +       mrs     x16, dbgwcr11_el1
> +       mrs     x15, dbgwcr10_el1
> +       mrs     x14, dbgwcr9_el1
> +       mrs     x13, dbgwcr8_el1
> +       mrs     x12, dbgwcr7_el1
> +       mrs     x11, dbgwcr6_el1
> +       mrs     x10, dbgwcr5_el1
> +       mrs     x9, dbgwcr4_el1
> +       mrs     x8, dbgwcr3_el1
> +       mrs     x7, dbgwcr2_el1
> +       mrs     x6, dbgwcr1_el1
> +       mrs     x5, dbgwcr0_el1
> +
> +       adr     x26, 1f
> +       add     x26, x26, x25, lsl #2
> +       br      x26
> +
> +1:
> +       str     x20, [x3, #(15 * 8)]
> +       str     x19, [x3, #(14 * 8)]
> +       str     x18, [x3, #(13 * 8)]
> +       str     x17, [x3, #(12 * 8)]
> +       str     x16, [x3, #(11 * 8)]
> +       str     x15, [x3, #(10 * 8)]
> +       str     x14, [x3, #(9 * 8)]
> +       str     x13, [x3, #(8 * 8)]
> +       str     x12, [x3, #(7 * 8)]
> +       str     x11, [x3, #(6 * 8)]
> +       str     x10, [x3, #(5 * 8)]
> +       str     x9, [x3, #(4 * 8)]
> +       str     x8, [x3, #(3 * 8)]
> +       str     x7, [x3, #(2 * 8)]
> +       str     x6, [x3, #(1 * 8)]
> +       str     x5, [x3, #(0 * 8)]
> +
> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
> +
> +       adr     x26, 1f
> +       add     x26, x26, x25, lsl #2
> +       br      x26
> +1:
> +       mrs     x20, dbgwvr15_el1
> +       mrs     x19, dbgwvr14_el1
> +       mrs     x18, dbgwvr13_el1
> +       mrs     x17, dbgwvr12_el1
> +       mrs     x16, dbgwvr11_el1
> +       mrs     x15, dbgwvr10_el1
> +       mrs     x14, dbgwvr9_el1
> +       mrs     x13, dbgwvr8_el1
> +       mrs     x12, dbgwvr7_el1
> +       mrs     x11, dbgwvr6_el1
> +       mrs     x10, dbgwvr5_el1
> +       mrs     x9, dbgwvr4_el1
> +       mrs     x8, dbgwvr3_el1
> +       mrs     x7, dbgwvr2_el1
> +       mrs     x6, dbgwvr1_el1
> +       mrs     x5, dbgwvr0_el1
> +
> +       adr     x26, 1f
> +       add     x26, x26, x25, lsl #2
> +       br      x26
> +
> +1:
> +       str     x20, [x3, #(15 * 8)]
> +       str     x19, [x3, #(14 * 8)]
> +       str     x18, [x3, #(13 * 8)]
> +       str     x17, [x3, #(12 * 8)]
> +       str     x16, [x3, #(11 * 8)]
> +       str     x15, [x3, #(10 * 8)]
> +       str     x14, [x3, #(9 * 8)]
> +       str     x13, [x3, #(8 * 8)]
> +       str     x12, [x3, #(7 * 8)]
> +       str     x11, [x3, #(6 * 8)]
> +       str     x10, [x3, #(5 * 8)]
> +       str     x9, [x3, #(4 * 8)]
> +       str     x8, [x3, #(3 * 8)]
> +       str     x7, [x3, #(2 * 8)]
> +       str     x6, [x3, #(1 * 8)]
> +       str     x5, [x3, #(0 * 8)]
> +
> +       mrs     x21, mdccint_el1
> +       str     x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
>  .endm
>
>  .macro restore_sysregs
> @@ -245,7 +442,7 @@ __kvm_hyp_code_start:
>         ldp     x18, x19, [x3, #112]
>         ldp     x20, x21, [x3, #128]
>         ldp     x22, x23, [x3, #144]
> -       ldr     x24, [x3, #160]
> +       ldp     x24, x25, [x3, #160]
>
>         msr     vmpidr_el2,     x4
>         msr     csselr_el1,     x5
> @@ -268,6 +465,198 @@ __kvm_hyp_code_start:
>         msr     amair_el1,      x22
>         msr     cntkctl_el1,    x23
>         msr     par_el1,        x24
> +       msr     mdscr_el1,      x25
> +.endm
> +
> +.macro restore_debug
> +       // x2: base address for cpu context
> +       // x3: tmp register
> +
> +       mrs     x26, id_aa64dfr0_el1
> +       ubfx    x24, x26, #12, #4       // Extract BRPs
> +       ubfx    x25, x26, #20, #4       // Extract WRPs
> +       mov     w26, #15
> +       sub     w24, w26, w24           // How many BPs to skip
> +       sub     w25, w26, w25           // How many WPs to skip
> +
> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
> +
> +       adr     x26, 1f
> +       add     x26, x26, x24, lsl #2
> +       br      x26
> +1:
> +       ldr     x20, [x3, #(15 * 8)]
> +       ldr     x19, [x3, #(14 * 8)]
> +       ldr     x18, [x3, #(13 * 8)]
> +       ldr     x17, [x3, #(12 * 8)]
> +       ldr     x16, [x3, #(11 * 8)]
> +       ldr     x15, [x3, #(10 * 8)]
> +       ldr     x14, [x3, #(9 * 8)]
> +       ldr     x13, [x3, #(8 * 8)]
> +       ldr     x12, [x3, #(7 * 8)]
> +       ldr     x11, [x3, #(6 * 8)]
> +       ldr     x10, [x3, #(5 * 8)]
> +       ldr     x9, [x3, #(4 * 8)]
> +       ldr     x8, [x3, #(3 * 8)]
> +       ldr     x7, [x3, #(2 * 8)]
> +       ldr     x6, [x3, #(1 * 8)]
> +       ldr     x5, [x3, #(0 * 8)]
> +
> +       adr     x26, 1f
> +       add     x26, x26, x24, lsl #2
> +       br      x26
> +1:
> +       msr     dbgbcr15_el1, x20
> +       msr     dbgbcr14_el1, x19
> +       msr     dbgbcr13_el1, x18
> +       msr     dbgbcr12_el1, x17
> +       msr     dbgbcr11_el1, x16
> +       msr     dbgbcr10_el1, x15
> +       msr     dbgbcr9_el1, x14
> +       msr     dbgbcr8_el1, x13
> +       msr     dbgbcr7_el1, x12
> +       msr     dbgbcr6_el1, x11
> +       msr     dbgbcr5_el1, x10
> +       msr     dbgbcr4_el1, x9
> +       msr     dbgbcr3_el1, x8
> +       msr     dbgbcr2_el1, x7
> +       msr     dbgbcr1_el1, x6
> +       msr     dbgbcr0_el1, x5
> +
> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
> +
> +       adr     x26, 1f
> +       add     x26, x26, x24, lsl #2
> +       br      x26
> +1:
> +       ldr     x20, [x3, #(15 * 8)]
> +       ldr     x19, [x3, #(14 * 8)]
> +       ldr     x18, [x3, #(13 * 8)]
> +       ldr     x17, [x3, #(12 * 8)]
> +       ldr     x16, [x3, #(11 * 8)]
> +       ldr     x15, [x3, #(10 * 8)]
> +       ldr     x14, [x3, #(9 * 8)]
> +       ldr     x13, [x3, #(8 * 8)]
> +       ldr     x12, [x3, #(7 * 8)]
> +       ldr     x11, [x3, #(6 * 8)]
> +       ldr     x10, [x3, #(5 * 8)]
> +       ldr     x9, [x3, #(4 * 8)]
> +       ldr     x8, [x3, #(3 * 8)]
> +       ldr     x7, [x3, #(2 * 8)]
> +       ldr     x6, [x3, #(1 * 8)]
> +       ldr     x5, [x3, #(0 * 8)]
> +
> +       adr     x26, 1f
> +       add     x26, x26, x24, lsl #2
> +       br      x26
> +1:
> +       msr     dbgbvr15_el1, x20
> +       msr     dbgbvr14_el1, x19
> +       msr     dbgbvr13_el1, x18
> +       msr     dbgbvr12_el1, x17
> +       msr     dbgbvr11_el1, x16
> +       msr     dbgbvr10_el1, x15
> +       msr     dbgbvr9_el1, x14
> +       msr     dbgbvr8_el1, x13
> +       msr     dbgbvr7_el1, x12
> +       msr     dbgbvr6_el1, x11
> +       msr     dbgbvr5_el1, x10
> +       msr     dbgbvr4_el1, x9
> +       msr     dbgbvr3_el1, x8
> +       msr     dbgbvr2_el1, x7
> +       msr     dbgbvr1_el1, x6
> +       msr     dbgbvr0_el1, x5
> +
> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
> +
> +       adr     x26, 1f
> +       add     x26, x26, x25, lsl #2
> +       br      x26
> +1:
> +       ldr     x20, [x3, #(15 * 8)]
> +       ldr     x19, [x3, #(14 * 8)]
> +       ldr     x18, [x3, #(13 * 8)]
> +       ldr     x17, [x3, #(12 * 8)]
> +       ldr     x16, [x3, #(11 * 8)]
> +       ldr     x15, [x3, #(10 * 8)]
> +       ldr     x14, [x3, #(9 * 8)]
> +       ldr     x13, [x3, #(8 * 8)]
> +       ldr     x12, [x3, #(7 * 8)]
> +       ldr     x11, [x3, #(6 * 8)]
> +       ldr     x10, [x3, #(5 * 8)]
> +       ldr     x9, [x3, #(4 * 8)]
> +       ldr     x8, [x3, #(3 * 8)]
> +       ldr     x7, [x3, #(2 * 8)]
> +       ldr     x6, [x3, #(1 * 8)]
> +       ldr     x5, [x3, #(0 * 8)]
> +
> +       adr     x26, 1f
> +       add     x26, x26, x25, lsl #2
> +       br      x26
> +1:
> +       msr     dbgwcr15_el1, x20
> +       msr     dbgwcr14_el1, x19
> +       msr     dbgwcr13_el1, x18
> +       msr     dbgwcr12_el1, x17
> +       msr     dbgwcr11_el1, x16
> +       msr     dbgwcr10_el1, x15
> +       msr     dbgwcr9_el1, x14
> +       msr     dbgwcr8_el1, x13
> +       msr     dbgwcr7_el1, x12
> +       msr     dbgwcr6_el1, x11
> +       msr     dbgwcr5_el1, x10
> +       msr     dbgwcr4_el1, x9
> +       msr     dbgwcr3_el1, x8
> +       msr     dbgwcr2_el1, x7
> +       msr     dbgwcr1_el1, x6
> +       msr     dbgwcr0_el1, x5
> +
> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
> +
> +       adr     x26, 1f
> +       add     x26, x26, x25, lsl #2
> +       br      x26
> +1:
> +       ldr     x20, [x3, #(15 * 8)]
> +       ldr     x19, [x3, #(14 * 8)]
> +       ldr     x18, [x3, #(13 * 8)]
> +       ldr     x17, [x3, #(12 * 8)]
> +       ldr     x16, [x3, #(11 * 8)]
> +       ldr     x15, [x3, #(10 * 8)]
> +       ldr     x14, [x3, #(9 * 8)]
> +       ldr     x13, [x3, #(8 * 8)]
> +       ldr     x12, [x3, #(7 * 8)]
> +       ldr     x11, [x3, #(6 * 8)]
> +       ldr     x10, [x3, #(5 * 8)]
> +       ldr     x9, [x3, #(4 * 8)]
> +       ldr     x8, [x3, #(3 * 8)]
> +       ldr     x7, [x3, #(2 * 8)]
> +       ldr     x6, [x3, #(1 * 8)]
> +       ldr     x5, [x3, #(0 * 8)]
> +
> +       adr     x26, 1f
> +       add     x26, x26, x25, lsl #2
> +       br      x26
> +1:
> +       msr     dbgwvr15_el1, x20
> +       msr     dbgwvr14_el1, x19
> +       msr     dbgwvr13_el1, x18
> +       msr     dbgwvr12_el1, x17
> +       msr     dbgwvr11_el1, x16
> +       msr     dbgwvr10_el1, x15
> +       msr     dbgwvr9_el1, x14
> +       msr     dbgwvr8_el1, x13
> +       msr     dbgwvr7_el1, x12
> +       msr     dbgwvr6_el1, x11
> +       msr     dbgwvr5_el1, x10
> +       msr     dbgwvr4_el1, x9
> +       msr     dbgwvr3_el1, x8
> +       msr     dbgwvr2_el1, x7
> +       msr     dbgwvr1_el1, x6
> +       msr     dbgwvr0_el1, x5
> +
> +       ldr     x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
> +       msr     mdccint_el1, x21
>  .endm
>
>  .macro skip_32bit_state tmp, target
> @@ -282,6 +671,11 @@ __kvm_hyp_code_start:
>         tbz     \tmp, #12, \target
>  .endm
>
> +.macro skip_clean_debug_state tmp, target
> +       ldr     \tmp, [x0, #VCPU_DEBUG_FLAGS]
> +       tbz     \tmp, #KVM_ARM64_DEBUG_DIRTY_SHIFT, \target
> +.endm
> +

At first glance, I was little confused by the macro name
skip_clean_debug_state.

I suggest to rename this macro to something like:
jump_to_label_if_debug_clean.

>  .macro save_guest_32bit_state
>         skip_32bit_state x3, 1f
>
> @@ -297,10 +691,13 @@ __kvm_hyp_code_start:
>         mrs     x4, dacr32_el2
>         mrs     x5, ifsr32_el2
>         mrs     x6, fpexc32_el2
> -       mrs     x7, dbgvcr32_el2
>         stp     x4, x5, [x3]
> -       stp     x6, x7, [x3, #16]
> +       str     x6, [x3, #16]
>
> +       skip_clean_debug_state x8, 2f
> +       mrs     x7, dbgvcr32_el2
> +       str     x7, [x3, #24]
> +2:
>         skip_tee_state x8, 1f
>
>         add     x3, x2, #CPU_SYSREG_OFFSET(TEECR32_EL1)
> @@ -323,12 +720,15 @@ __kvm_hyp_code_start:
>
>         add     x3, x2, #CPU_SYSREG_OFFSET(DACR32_EL2)
>         ldp     x4, x5, [x3]
> -       ldp     x6, x7, [x3, #16]
> +       ldr     x6, [x3, #16]
>         msr     dacr32_el2, x4
>         msr     ifsr32_el2, x5
>         msr     fpexc32_el2, x6
> -       msr     dbgvcr32_el2, x7
>
> +       skip_clean_debug_state x8, 2f
> +       ldr     x7, [x3, #24]
> +       msr     dbgvcr32_el2, x7
> +2:
>         skip_tee_state x8, 1f
>
>         add     x3, x2, #CPU_SYSREG_OFFSET(TEECR32_EL1)
> @@ -537,6 +937,14 @@ __restore_sysregs:
>         restore_sysregs
>         ret
>
> +__save_debug:
> +       save_debug
> +       ret
> +
> +__restore_debug:
> +       restore_debug
> +       ret
> +
>  __save_fpsimd:
>         save_fpsimd
>         ret
> @@ -568,6 +976,21 @@ ENTRY(__kvm_vcpu_run)
>         bl __save_fpsimd
>         bl __save_sysregs
>
> +       // Compute debug state: If any of KDE, MDE or KVM_ARM64_DEBUG_DIRTY
> +       // is set, we do a full save/restore cycle and disable trapping.
> +       add     x25, x0, #VCPU_CONTEXT
> +       ldr     x25, [x25, #CPU_SYSREG_OFFSET(MDSCR_EL1)]
> +       and     x26, x25, #DBG_MDSCR_KDE
> +       and     x25, x25, #DBG_MDSCR_MDE
> +       adds    xzr, x25, x26
> +       mov     x26, #KVM_ARM64_DEBUG_DIRTY
> +       csel    x25, x26, xzr, ne
> +       ldr     x26, [x0, #VCPU_DEBUG_FLAGS]
> +       orr     x26, x26, x25
> +       cbz     x26, 1f
> +       str     x26, [x0, #VCPU_DEBUG_FLAGS]
> +       bl      __save_debug
> +1:
>         activate_traps
>         activate_vm
>
> @@ -579,6 +1002,10 @@ ENTRY(__kvm_vcpu_run)
>
>         bl __restore_sysregs
>         bl __restore_fpsimd
> +
> +       skip_clean_debug_state x3, 1f
> +       bl      __restore_debug
> +1:
>         restore_guest_32bit_state
>         restore_guest_regs
>
> @@ -595,6 +1022,10 @@ __kvm_vcpu_return:
>         save_guest_regs
>         bl __save_fpsimd
>         bl __save_sysregs
> +
> +       skip_clean_debug_state x3, 1f
> +       bl      __save_debug
> +1:
>         save_guest_32bit_state
>
>         save_timer_state
> @@ -609,6 +1040,12 @@ __kvm_vcpu_return:
>
>         bl __restore_sysregs
>         bl __restore_fpsimd
> +
> +       skip_clean_debug_state x3, 1f
> +       // Clear the dirty flag for the next run
> +       str     xzr, [x0, #VCPU_DEBUG_FLAGS]
> +       bl      __restore_debug
> +1:
>         restore_host_regs
>
>         mov     x0, x1
> --
> 1.8.3.4
>
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

Other than the minor comment mentioned above this looks
good to me.

FWIW, Reviewed-by: Anup Patel <anup.patel@linaro.org>

--
Anup
Marc Zyngier May 19, 2014, 4:01 p.m. UTC | #2
On 19/05/14 09:38, Anup Patel wrote:
> On 7 May 2014 20:50, Marc Zyngier <marc.zyngier@arm.com> wrote:
>> Implement switching of the debug registers. While the number
>> of registers is massive, CPUs usually don't implement them all
>> (A57 has 6 breakpoints and 4 watchpoints, which gives us a total
>> of 22 registers "only").
>>
>> Also, we only save/restore them when MDSCR_EL1 has debug enabled,
>> or when we've flagged the debug registers as dirty. It means that
>> most of the time, we only save/restore MDSCR_EL1.
>>
>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>> ---
>>  arch/arm64/kernel/asm-offsets.c |   1 +
>>  arch/arm64/kvm/hyp.S            | 449 +++++++++++++++++++++++++++++++++++++++-
>>  2 files changed, 444 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
>> index 646f888..ae73a83 100644
>> --- a/arch/arm64/kernel/asm-offsets.c
>> +++ b/arch/arm64/kernel/asm-offsets.c
>> @@ -120,6 +120,7 @@ int main(void)
>>    DEFINE(VCPU_ESR_EL2,         offsetof(struct kvm_vcpu, arch.fault.esr_el2));
>>    DEFINE(VCPU_FAR_EL2,         offsetof(struct kvm_vcpu, arch.fault.far_el2));
>>    DEFINE(VCPU_HPFAR_EL2,       offsetof(struct kvm_vcpu, arch.fault.hpfar_el2));
>> +  DEFINE(VCPU_DEBUG_FLAGS,     offsetof(struct kvm_vcpu, arch.debug_flags));
>>    DEFINE(VCPU_HCR_EL2,         offsetof(struct kvm_vcpu, arch.hcr_el2));
>>    DEFINE(VCPU_IRQ_LINES,       offsetof(struct kvm_vcpu, arch.irq_lines));
>>    DEFINE(VCPU_HOST_CONTEXT,    offsetof(struct kvm_vcpu, arch.host_cpu_context));
>> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
>> index 2c56012..f9d5a1d 100644
>> --- a/arch/arm64/kvm/hyp.S
>> +++ b/arch/arm64/kvm/hyp.S
>> @@ -21,6 +21,7 @@
>>  #include <asm/assembler.h>
>>  #include <asm/memory.h>
>>  #include <asm/asm-offsets.h>
>> +#include <asm/debug-monitors.h>
>>  #include <asm/fpsimdmacros.h>
>>  #include <asm/kvm.h>
>>  #include <asm/kvm_asm.h>
>> @@ -215,6 +216,7 @@ __kvm_hyp_code_start:
>>         mrs     x22,    amair_el1
>>         mrs     x23,    cntkctl_el1
>>         mrs     x24,    par_el1
>> +       mrs     x25,    mdscr_el1
>>
>>         stp     x4, x5, [x3]
>>         stp     x6, x7, [x3, #16]
>> @@ -226,7 +228,202 @@ __kvm_hyp_code_start:
>>         stp     x18, x19, [x3, #112]
>>         stp     x20, x21, [x3, #128]
>>         stp     x22, x23, [x3, #144]
>> -       str     x24, [x3, #160]
>> +       stp     x24, x25, [x3, #160]
>> +.endm
>> +
>> +.macro save_debug
>> +       // x2: base address for cpu context
>> +       // x3: tmp register
>> +
>> +       mrs     x26, id_aa64dfr0_el1
>> +       ubfx    x24, x26, #12, #4       // Extract BRPs
>> +       ubfx    x25, x26, #20, #4       // Extract WRPs
>> +       mov     w26, #15
>> +       sub     w24, w26, w24           // How many BPs to skip
>> +       sub     w25, w26, w25           // How many WPs to skip
>> +
>> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x24, lsl #2
>> +       br      x26
>> +1:
>> +       mrs     x20, dbgbcr15_el1
>> +       mrs     x19, dbgbcr14_el1
>> +       mrs     x18, dbgbcr13_el1
>> +       mrs     x17, dbgbcr12_el1
>> +       mrs     x16, dbgbcr11_el1
>> +       mrs     x15, dbgbcr10_el1
>> +       mrs     x14, dbgbcr9_el1
>> +       mrs     x13, dbgbcr8_el1
>> +       mrs     x12, dbgbcr7_el1
>> +       mrs     x11, dbgbcr6_el1
>> +       mrs     x10, dbgbcr5_el1
>> +       mrs     x9, dbgbcr4_el1
>> +       mrs     x8, dbgbcr3_el1
>> +       mrs     x7, dbgbcr2_el1
>> +       mrs     x6, dbgbcr1_el1
>> +       mrs     x5, dbgbcr0_el1
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x24, lsl #2
>> +       br      x26
>> +
>> +1:
>> +       str     x20, [x3, #(15 * 8)]
>> +       str     x19, [x3, #(14 * 8)]
>> +       str     x18, [x3, #(13 * 8)]
>> +       str     x17, [x3, #(12 * 8)]
>> +       str     x16, [x3, #(11 * 8)]
>> +       str     x15, [x3, #(10 * 8)]
>> +       str     x14, [x3, #(9 * 8)]
>> +       str     x13, [x3, #(8 * 8)]
>> +       str     x12, [x3, #(7 * 8)]
>> +       str     x11, [x3, #(6 * 8)]
>> +       str     x10, [x3, #(5 * 8)]
>> +       str     x9, [x3, #(4 * 8)]
>> +       str     x8, [x3, #(3 * 8)]
>> +       str     x7, [x3, #(2 * 8)]
>> +       str     x6, [x3, #(1 * 8)]
>> +       str     x5, [x3, #(0 * 8)]
>> +
>> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x24, lsl #2
>> +       br      x26
>> +1:
>> +       mrs     x20, dbgbvr15_el1
>> +       mrs     x19, dbgbvr14_el1
>> +       mrs     x18, dbgbvr13_el1
>> +       mrs     x17, dbgbvr12_el1
>> +       mrs     x16, dbgbvr11_el1
>> +       mrs     x15, dbgbvr10_el1
>> +       mrs     x14, dbgbvr9_el1
>> +       mrs     x13, dbgbvr8_el1
>> +       mrs     x12, dbgbvr7_el1
>> +       mrs     x11, dbgbvr6_el1
>> +       mrs     x10, dbgbvr5_el1
>> +       mrs     x9, dbgbvr4_el1
>> +       mrs     x8, dbgbvr3_el1
>> +       mrs     x7, dbgbvr2_el1
>> +       mrs     x6, dbgbvr1_el1
>> +       mrs     x5, dbgbvr0_el1
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x24, lsl #2
>> +       br      x26
>> +
>> +1:
>> +       str     x20, [x3, #(15 * 8)]
>> +       str     x19, [x3, #(14 * 8)]
>> +       str     x18, [x3, #(13 * 8)]
>> +       str     x17, [x3, #(12 * 8)]
>> +       str     x16, [x3, #(11 * 8)]
>> +       str     x15, [x3, #(10 * 8)]
>> +       str     x14, [x3, #(9 * 8)]
>> +       str     x13, [x3, #(8 * 8)]
>> +       str     x12, [x3, #(7 * 8)]
>> +       str     x11, [x3, #(6 * 8)]
>> +       str     x10, [x3, #(5 * 8)]
>> +       str     x9, [x3, #(4 * 8)]
>> +       str     x8, [x3, #(3 * 8)]
>> +       str     x7, [x3, #(2 * 8)]
>> +       str     x6, [x3, #(1 * 8)]
>> +       str     x5, [x3, #(0 * 8)]
>> +
>> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x25, lsl #2
>> +       br      x26
>> +1:
>> +       mrs     x20, dbgwcr15_el1
>> +       mrs     x19, dbgwcr14_el1
>> +       mrs     x18, dbgwcr13_el1
>> +       mrs     x17, dbgwcr12_el1
>> +       mrs     x16, dbgwcr11_el1
>> +       mrs     x15, dbgwcr10_el1
>> +       mrs     x14, dbgwcr9_el1
>> +       mrs     x13, dbgwcr8_el1
>> +       mrs     x12, dbgwcr7_el1
>> +       mrs     x11, dbgwcr6_el1
>> +       mrs     x10, dbgwcr5_el1
>> +       mrs     x9, dbgwcr4_el1
>> +       mrs     x8, dbgwcr3_el1
>> +       mrs     x7, dbgwcr2_el1
>> +       mrs     x6, dbgwcr1_el1
>> +       mrs     x5, dbgwcr0_el1
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x25, lsl #2
>> +       br      x26
>> +
>> +1:
>> +       str     x20, [x3, #(15 * 8)]
>> +       str     x19, [x3, #(14 * 8)]
>> +       str     x18, [x3, #(13 * 8)]
>> +       str     x17, [x3, #(12 * 8)]
>> +       str     x16, [x3, #(11 * 8)]
>> +       str     x15, [x3, #(10 * 8)]
>> +       str     x14, [x3, #(9 * 8)]
>> +       str     x13, [x3, #(8 * 8)]
>> +       str     x12, [x3, #(7 * 8)]
>> +       str     x11, [x3, #(6 * 8)]
>> +       str     x10, [x3, #(5 * 8)]
>> +       str     x9, [x3, #(4 * 8)]
>> +       str     x8, [x3, #(3 * 8)]
>> +       str     x7, [x3, #(2 * 8)]
>> +       str     x6, [x3, #(1 * 8)]
>> +       str     x5, [x3, #(0 * 8)]
>> +
>> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x25, lsl #2
>> +       br      x26
>> +1:
>> +       mrs     x20, dbgwvr15_el1
>> +       mrs     x19, dbgwvr14_el1
>> +       mrs     x18, dbgwvr13_el1
>> +       mrs     x17, dbgwvr12_el1
>> +       mrs     x16, dbgwvr11_el1
>> +       mrs     x15, dbgwvr10_el1
>> +       mrs     x14, dbgwvr9_el1
>> +       mrs     x13, dbgwvr8_el1
>> +       mrs     x12, dbgwvr7_el1
>> +       mrs     x11, dbgwvr6_el1
>> +       mrs     x10, dbgwvr5_el1
>> +       mrs     x9, dbgwvr4_el1
>> +       mrs     x8, dbgwvr3_el1
>> +       mrs     x7, dbgwvr2_el1
>> +       mrs     x6, dbgwvr1_el1
>> +       mrs     x5, dbgwvr0_el1
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x25, lsl #2
>> +       br      x26
>> +
>> +1:
>> +       str     x20, [x3, #(15 * 8)]
>> +       str     x19, [x3, #(14 * 8)]
>> +       str     x18, [x3, #(13 * 8)]
>> +       str     x17, [x3, #(12 * 8)]
>> +       str     x16, [x3, #(11 * 8)]
>> +       str     x15, [x3, #(10 * 8)]
>> +       str     x14, [x3, #(9 * 8)]
>> +       str     x13, [x3, #(8 * 8)]
>> +       str     x12, [x3, #(7 * 8)]
>> +       str     x11, [x3, #(6 * 8)]
>> +       str     x10, [x3, #(5 * 8)]
>> +       str     x9, [x3, #(4 * 8)]
>> +       str     x8, [x3, #(3 * 8)]
>> +       str     x7, [x3, #(2 * 8)]
>> +       str     x6, [x3, #(1 * 8)]
>> +       str     x5, [x3, #(0 * 8)]
>> +
>> +       mrs     x21, mdccint_el1
>> +       str     x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
>>  .endm
>>
>>  .macro restore_sysregs
>> @@ -245,7 +442,7 @@ __kvm_hyp_code_start:
>>         ldp     x18, x19, [x3, #112]
>>         ldp     x20, x21, [x3, #128]
>>         ldp     x22, x23, [x3, #144]
>> -       ldr     x24, [x3, #160]
>> +       ldp     x24, x25, [x3, #160]
>>
>>         msr     vmpidr_el2,     x4
>>         msr     csselr_el1,     x5
>> @@ -268,6 +465,198 @@ __kvm_hyp_code_start:
>>         msr     amair_el1,      x22
>>         msr     cntkctl_el1,    x23
>>         msr     par_el1,        x24
>> +       msr     mdscr_el1,      x25
>> +.endm
>> +
>> +.macro restore_debug
>> +       // x2: base address for cpu context
>> +       // x3: tmp register
>> +
>> +       mrs     x26, id_aa64dfr0_el1
>> +       ubfx    x24, x26, #12, #4       // Extract BRPs
>> +       ubfx    x25, x26, #20, #4       // Extract WRPs
>> +       mov     w26, #15
>> +       sub     w24, w26, w24           // How many BPs to skip
>> +       sub     w25, w26, w25           // How many WPs to skip
>> +
>> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x24, lsl #2
>> +       br      x26
>> +1:
>> +       ldr     x20, [x3, #(15 * 8)]
>> +       ldr     x19, [x3, #(14 * 8)]
>> +       ldr     x18, [x3, #(13 * 8)]
>> +       ldr     x17, [x3, #(12 * 8)]
>> +       ldr     x16, [x3, #(11 * 8)]
>> +       ldr     x15, [x3, #(10 * 8)]
>> +       ldr     x14, [x3, #(9 * 8)]
>> +       ldr     x13, [x3, #(8 * 8)]
>> +       ldr     x12, [x3, #(7 * 8)]
>> +       ldr     x11, [x3, #(6 * 8)]
>> +       ldr     x10, [x3, #(5 * 8)]
>> +       ldr     x9, [x3, #(4 * 8)]
>> +       ldr     x8, [x3, #(3 * 8)]
>> +       ldr     x7, [x3, #(2 * 8)]
>> +       ldr     x6, [x3, #(1 * 8)]
>> +       ldr     x5, [x3, #(0 * 8)]
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x24, lsl #2
>> +       br      x26
>> +1:
>> +       msr     dbgbcr15_el1, x20
>> +       msr     dbgbcr14_el1, x19
>> +       msr     dbgbcr13_el1, x18
>> +       msr     dbgbcr12_el1, x17
>> +       msr     dbgbcr11_el1, x16
>> +       msr     dbgbcr10_el1, x15
>> +       msr     dbgbcr9_el1, x14
>> +       msr     dbgbcr8_el1, x13
>> +       msr     dbgbcr7_el1, x12
>> +       msr     dbgbcr6_el1, x11
>> +       msr     dbgbcr5_el1, x10
>> +       msr     dbgbcr4_el1, x9
>> +       msr     dbgbcr3_el1, x8
>> +       msr     dbgbcr2_el1, x7
>> +       msr     dbgbcr1_el1, x6
>> +       msr     dbgbcr0_el1, x5
>> +
>> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x24, lsl #2
>> +       br      x26
>> +1:
>> +       ldr     x20, [x3, #(15 * 8)]
>> +       ldr     x19, [x3, #(14 * 8)]
>> +       ldr     x18, [x3, #(13 * 8)]
>> +       ldr     x17, [x3, #(12 * 8)]
>> +       ldr     x16, [x3, #(11 * 8)]
>> +       ldr     x15, [x3, #(10 * 8)]
>> +       ldr     x14, [x3, #(9 * 8)]
>> +       ldr     x13, [x3, #(8 * 8)]
>> +       ldr     x12, [x3, #(7 * 8)]
>> +       ldr     x11, [x3, #(6 * 8)]
>> +       ldr     x10, [x3, #(5 * 8)]
>> +       ldr     x9, [x3, #(4 * 8)]
>> +       ldr     x8, [x3, #(3 * 8)]
>> +       ldr     x7, [x3, #(2 * 8)]
>> +       ldr     x6, [x3, #(1 * 8)]
>> +       ldr     x5, [x3, #(0 * 8)]
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x24, lsl #2
>> +       br      x26
>> +1:
>> +       msr     dbgbvr15_el1, x20
>> +       msr     dbgbvr14_el1, x19
>> +       msr     dbgbvr13_el1, x18
>> +       msr     dbgbvr12_el1, x17
>> +       msr     dbgbvr11_el1, x16
>> +       msr     dbgbvr10_el1, x15
>> +       msr     dbgbvr9_el1, x14
>> +       msr     dbgbvr8_el1, x13
>> +       msr     dbgbvr7_el1, x12
>> +       msr     dbgbvr6_el1, x11
>> +       msr     dbgbvr5_el1, x10
>> +       msr     dbgbvr4_el1, x9
>> +       msr     dbgbvr3_el1, x8
>> +       msr     dbgbvr2_el1, x7
>> +       msr     dbgbvr1_el1, x6
>> +       msr     dbgbvr0_el1, x5
>> +
>> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x25, lsl #2
>> +       br      x26
>> +1:
>> +       ldr     x20, [x3, #(15 * 8)]
>> +       ldr     x19, [x3, #(14 * 8)]
>> +       ldr     x18, [x3, #(13 * 8)]
>> +       ldr     x17, [x3, #(12 * 8)]
>> +       ldr     x16, [x3, #(11 * 8)]
>> +       ldr     x15, [x3, #(10 * 8)]
>> +       ldr     x14, [x3, #(9 * 8)]
>> +       ldr     x13, [x3, #(8 * 8)]
>> +       ldr     x12, [x3, #(7 * 8)]
>> +       ldr     x11, [x3, #(6 * 8)]
>> +       ldr     x10, [x3, #(5 * 8)]
>> +       ldr     x9, [x3, #(4 * 8)]
>> +       ldr     x8, [x3, #(3 * 8)]
>> +       ldr     x7, [x3, #(2 * 8)]
>> +       ldr     x6, [x3, #(1 * 8)]
>> +       ldr     x5, [x3, #(0 * 8)]
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x25, lsl #2
>> +       br      x26
>> +1:
>> +       msr     dbgwcr15_el1, x20
>> +       msr     dbgwcr14_el1, x19
>> +       msr     dbgwcr13_el1, x18
>> +       msr     dbgwcr12_el1, x17
>> +       msr     dbgwcr11_el1, x16
>> +       msr     dbgwcr10_el1, x15
>> +       msr     dbgwcr9_el1, x14
>> +       msr     dbgwcr8_el1, x13
>> +       msr     dbgwcr7_el1, x12
>> +       msr     dbgwcr6_el1, x11
>> +       msr     dbgwcr5_el1, x10
>> +       msr     dbgwcr4_el1, x9
>> +       msr     dbgwcr3_el1, x8
>> +       msr     dbgwcr2_el1, x7
>> +       msr     dbgwcr1_el1, x6
>> +       msr     dbgwcr0_el1, x5
>> +
>> +       add     x3, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x25, lsl #2
>> +       br      x26
>> +1:
>> +       ldr     x20, [x3, #(15 * 8)]
>> +       ldr     x19, [x3, #(14 * 8)]
>> +       ldr     x18, [x3, #(13 * 8)]
>> +       ldr     x17, [x3, #(12 * 8)]
>> +       ldr     x16, [x3, #(11 * 8)]
>> +       ldr     x15, [x3, #(10 * 8)]
>> +       ldr     x14, [x3, #(9 * 8)]
>> +       ldr     x13, [x3, #(8 * 8)]
>> +       ldr     x12, [x3, #(7 * 8)]
>> +       ldr     x11, [x3, #(6 * 8)]
>> +       ldr     x10, [x3, #(5 * 8)]
>> +       ldr     x9, [x3, #(4 * 8)]
>> +       ldr     x8, [x3, #(3 * 8)]
>> +       ldr     x7, [x3, #(2 * 8)]
>> +       ldr     x6, [x3, #(1 * 8)]
>> +       ldr     x5, [x3, #(0 * 8)]
>> +
>> +       adr     x26, 1f
>> +       add     x26, x26, x25, lsl #2
>> +       br      x26
>> +1:
>> +       msr     dbgwvr15_el1, x20
>> +       msr     dbgwvr14_el1, x19
>> +       msr     dbgwvr13_el1, x18
>> +       msr     dbgwvr12_el1, x17
>> +       msr     dbgwvr11_el1, x16
>> +       msr     dbgwvr10_el1, x15
>> +       msr     dbgwvr9_el1, x14
>> +       msr     dbgwvr8_el1, x13
>> +       msr     dbgwvr7_el1, x12
>> +       msr     dbgwvr6_el1, x11
>> +       msr     dbgwvr5_el1, x10
>> +       msr     dbgwvr4_el1, x9
>> +       msr     dbgwvr3_el1, x8
>> +       msr     dbgwvr2_el1, x7
>> +       msr     dbgwvr1_el1, x6
>> +       msr     dbgwvr0_el1, x5
>> +
>> +       ldr     x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
>> +       msr     mdccint_el1, x21
>>  .endm
>>
>>  .macro skip_32bit_state tmp, target
>> @@ -282,6 +671,11 @@ __kvm_hyp_code_start:
>>         tbz     \tmp, #12, \target
>>  .endm
>>
>> +.macro skip_clean_debug_state tmp, target
>> +       ldr     \tmp, [x0, #VCPU_DEBUG_FLAGS]
>> +       tbz     \tmp, #KVM_ARM64_DEBUG_DIRTY_SHIFT, \target
>> +.endm
>> +
> 
> At first glance, I was little confused by the macro name
> skip_clean_debug_state.
> 
> I suggest to rename this macro to something like:
> jump_to_label_if_debug_clean.

Well, we already have:
- skip_32bit_state
- skip_tee_state

Both mean "skip xxx state if not not useful in the vcpu context".
Maybe simplifying it to just read "skip_debug_state"?

Christoffer, you're much better at naming stuff than I am. Any idea?

Thanks,

	M.
diff mbox

Patch

diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 646f888..ae73a83 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -120,6 +120,7 @@  int main(void)
   DEFINE(VCPU_ESR_EL2,		offsetof(struct kvm_vcpu, arch.fault.esr_el2));
   DEFINE(VCPU_FAR_EL2,		offsetof(struct kvm_vcpu, arch.fault.far_el2));
   DEFINE(VCPU_HPFAR_EL2,	offsetof(struct kvm_vcpu, arch.fault.hpfar_el2));
+  DEFINE(VCPU_DEBUG_FLAGS,	offsetof(struct kvm_vcpu, arch.debug_flags));
   DEFINE(VCPU_HCR_EL2,		offsetof(struct kvm_vcpu, arch.hcr_el2));
   DEFINE(VCPU_IRQ_LINES,	offsetof(struct kvm_vcpu, arch.irq_lines));
   DEFINE(VCPU_HOST_CONTEXT,	offsetof(struct kvm_vcpu, arch.host_cpu_context));
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 2c56012..f9d5a1d 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -21,6 +21,7 @@ 
 #include <asm/assembler.h>
 #include <asm/memory.h>
 #include <asm/asm-offsets.h>
+#include <asm/debug-monitors.h>
 #include <asm/fpsimdmacros.h>
 #include <asm/kvm.h>
 #include <asm/kvm_asm.h>
@@ -215,6 +216,7 @@  __kvm_hyp_code_start:
 	mrs	x22, 	amair_el1
 	mrs	x23, 	cntkctl_el1
 	mrs	x24,	par_el1
+	mrs	x25,	mdscr_el1
 
 	stp	x4, x5, [x3]
 	stp	x6, x7, [x3, #16]
@@ -226,7 +228,202 @@  __kvm_hyp_code_start:
 	stp	x18, x19, [x3, #112]
 	stp	x20, x21, [x3, #128]
 	stp	x22, x23, [x3, #144]
-	str	x24, [x3, #160]
+	stp	x24, x25, [x3, #160]
+.endm
+
+.macro save_debug
+	// x2: base address for cpu context
+	// x3: tmp register
+
+	mrs	x26, id_aa64dfr0_el1
+	ubfx	x24, x26, #12, #4	// Extract BRPs
+	ubfx	x25, x26, #20, #4	// Extract WRPs
+	mov	w26, #15
+	sub	w24, w26, w24		// How many BPs to skip
+	sub	w25, w26, w25		// How many WPs to skip
+
+	add	x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
+
+	adr	x26, 1f
+	add	x26, x26, x24, lsl #2
+	br	x26
+1:
+	mrs	x20, dbgbcr15_el1
+	mrs	x19, dbgbcr14_el1
+	mrs	x18, dbgbcr13_el1
+	mrs	x17, dbgbcr12_el1
+	mrs	x16, dbgbcr11_el1
+	mrs	x15, dbgbcr10_el1
+	mrs	x14, dbgbcr9_el1
+	mrs	x13, dbgbcr8_el1
+	mrs	x12, dbgbcr7_el1
+	mrs	x11, dbgbcr6_el1
+	mrs	x10, dbgbcr5_el1
+	mrs	x9, dbgbcr4_el1
+	mrs	x8, dbgbcr3_el1
+	mrs	x7, dbgbcr2_el1
+	mrs	x6, dbgbcr1_el1
+	mrs	x5, dbgbcr0_el1
+
+	adr	x26, 1f
+	add	x26, x26, x24, lsl #2
+	br	x26
+
+1:
+	str	x20, [x3, #(15 * 8)]
+	str	x19, [x3, #(14 * 8)]
+	str	x18, [x3, #(13 * 8)]
+	str	x17, [x3, #(12 * 8)]
+	str	x16, [x3, #(11 * 8)]
+	str	x15, [x3, #(10 * 8)]
+	str	x14, [x3, #(9 * 8)]
+	str	x13, [x3, #(8 * 8)]
+	str	x12, [x3, #(7 * 8)]
+	str	x11, [x3, #(6 * 8)]
+	str	x10, [x3, #(5 * 8)]
+	str	x9, [x3, #(4 * 8)]
+	str	x8, [x3, #(3 * 8)]
+	str	x7, [x3, #(2 * 8)]
+	str	x6, [x3, #(1 * 8)]
+	str	x5, [x3, #(0 * 8)]
+
+	add	x3, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
+
+	adr	x26, 1f
+	add	x26, x26, x24, lsl #2
+	br	x26
+1:
+	mrs	x20, dbgbvr15_el1
+	mrs	x19, dbgbvr14_el1
+	mrs	x18, dbgbvr13_el1
+	mrs	x17, dbgbvr12_el1
+	mrs	x16, dbgbvr11_el1
+	mrs	x15, dbgbvr10_el1
+	mrs	x14, dbgbvr9_el1
+	mrs	x13, dbgbvr8_el1
+	mrs	x12, dbgbvr7_el1
+	mrs	x11, dbgbvr6_el1
+	mrs	x10, dbgbvr5_el1
+	mrs	x9, dbgbvr4_el1
+	mrs	x8, dbgbvr3_el1
+	mrs	x7, dbgbvr2_el1
+	mrs	x6, dbgbvr1_el1
+	mrs	x5, dbgbvr0_el1
+
+	adr	x26, 1f
+	add	x26, x26, x24, lsl #2
+	br	x26
+
+1:
+	str	x20, [x3, #(15 * 8)]
+	str	x19, [x3, #(14 * 8)]
+	str	x18, [x3, #(13 * 8)]
+	str	x17, [x3, #(12 * 8)]
+	str	x16, [x3, #(11 * 8)]
+	str	x15, [x3, #(10 * 8)]
+	str	x14, [x3, #(9 * 8)]
+	str	x13, [x3, #(8 * 8)]
+	str	x12, [x3, #(7 * 8)]
+	str	x11, [x3, #(6 * 8)]
+	str	x10, [x3, #(5 * 8)]
+	str	x9, [x3, #(4 * 8)]
+	str	x8, [x3, #(3 * 8)]
+	str	x7, [x3, #(2 * 8)]
+	str	x6, [x3, #(1 * 8)]
+	str	x5, [x3, #(0 * 8)]
+
+	add	x3, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
+
+	adr	x26, 1f
+	add	x26, x26, x25, lsl #2
+	br	x26
+1:
+	mrs	x20, dbgwcr15_el1
+	mrs	x19, dbgwcr14_el1
+	mrs	x18, dbgwcr13_el1
+	mrs	x17, dbgwcr12_el1
+	mrs	x16, dbgwcr11_el1
+	mrs	x15, dbgwcr10_el1
+	mrs	x14, dbgwcr9_el1
+	mrs	x13, dbgwcr8_el1
+	mrs	x12, dbgwcr7_el1
+	mrs	x11, dbgwcr6_el1
+	mrs	x10, dbgwcr5_el1
+	mrs	x9, dbgwcr4_el1
+	mrs	x8, dbgwcr3_el1
+	mrs	x7, dbgwcr2_el1
+	mrs	x6, dbgwcr1_el1
+	mrs	x5, dbgwcr0_el1
+
+	adr	x26, 1f
+	add	x26, x26, x25, lsl #2
+	br	x26
+
+1:
+	str	x20, [x3, #(15 * 8)]
+	str	x19, [x3, #(14 * 8)]
+	str	x18, [x3, #(13 * 8)]
+	str	x17, [x3, #(12 * 8)]
+	str	x16, [x3, #(11 * 8)]
+	str	x15, [x3, #(10 * 8)]
+	str	x14, [x3, #(9 * 8)]
+	str	x13, [x3, #(8 * 8)]
+	str	x12, [x3, #(7 * 8)]
+	str	x11, [x3, #(6 * 8)]
+	str	x10, [x3, #(5 * 8)]
+	str	x9, [x3, #(4 * 8)]
+	str	x8, [x3, #(3 * 8)]
+	str	x7, [x3, #(2 * 8)]
+	str	x6, [x3, #(1 * 8)]
+	str	x5, [x3, #(0 * 8)]
+
+	add	x3, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
+
+	adr	x26, 1f
+	add	x26, x26, x25, lsl #2
+	br	x26
+1:
+	mrs	x20, dbgwvr15_el1
+	mrs	x19, dbgwvr14_el1
+	mrs	x18, dbgwvr13_el1
+	mrs	x17, dbgwvr12_el1
+	mrs	x16, dbgwvr11_el1
+	mrs	x15, dbgwvr10_el1
+	mrs	x14, dbgwvr9_el1
+	mrs	x13, dbgwvr8_el1
+	mrs	x12, dbgwvr7_el1
+	mrs	x11, dbgwvr6_el1
+	mrs	x10, dbgwvr5_el1
+	mrs	x9, dbgwvr4_el1
+	mrs	x8, dbgwvr3_el1
+	mrs	x7, dbgwvr2_el1
+	mrs	x6, dbgwvr1_el1
+	mrs	x5, dbgwvr0_el1
+
+	adr	x26, 1f
+	add	x26, x26, x25, lsl #2
+	br	x26
+
+1:
+	str	x20, [x3, #(15 * 8)]
+	str	x19, [x3, #(14 * 8)]
+	str	x18, [x3, #(13 * 8)]
+	str	x17, [x3, #(12 * 8)]
+	str	x16, [x3, #(11 * 8)]
+	str	x15, [x3, #(10 * 8)]
+	str	x14, [x3, #(9 * 8)]
+	str	x13, [x3, #(8 * 8)]
+	str	x12, [x3, #(7 * 8)]
+	str	x11, [x3, #(6 * 8)]
+	str	x10, [x3, #(5 * 8)]
+	str	x9, [x3, #(4 * 8)]
+	str	x8, [x3, #(3 * 8)]
+	str	x7, [x3, #(2 * 8)]
+	str	x6, [x3, #(1 * 8)]
+	str	x5, [x3, #(0 * 8)]
+
+	mrs	x21, mdccint_el1
+	str	x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
 .endm
 
 .macro restore_sysregs
@@ -245,7 +442,7 @@  __kvm_hyp_code_start:
 	ldp	x18, x19, [x3, #112]
 	ldp	x20, x21, [x3, #128]
 	ldp	x22, x23, [x3, #144]
-	ldr	x24, [x3, #160]
+	ldp	x24, x25, [x3, #160]
 
 	msr	vmpidr_el2,	x4
 	msr	csselr_el1,	x5
@@ -268,6 +465,198 @@  __kvm_hyp_code_start:
 	msr	amair_el1,	x22
 	msr	cntkctl_el1,	x23
 	msr	par_el1,	x24
+	msr	mdscr_el1,	x25
+.endm
+
+.macro restore_debug
+	// x2: base address for cpu context
+	// x3: tmp register
+
+	mrs	x26, id_aa64dfr0_el1
+	ubfx	x24, x26, #12, #4	// Extract BRPs
+	ubfx	x25, x26, #20, #4	// Extract WRPs
+	mov	w26, #15
+	sub	w24, w26, w24		// How many BPs to skip
+	sub	w25, w26, w25		// How many WPs to skip
+
+	add	x3, x2, #CPU_SYSREG_OFFSET(DBGBCR0_EL1)
+
+	adr	x26, 1f
+	add	x26, x26, x24, lsl #2
+	br	x26
+1:
+	ldr	x20, [x3, #(15 * 8)]
+	ldr	x19, [x3, #(14 * 8)]
+	ldr	x18, [x3, #(13 * 8)]
+	ldr	x17, [x3, #(12 * 8)]
+	ldr	x16, [x3, #(11 * 8)]
+	ldr	x15, [x3, #(10 * 8)]
+	ldr	x14, [x3, #(9 * 8)]
+	ldr	x13, [x3, #(8 * 8)]
+	ldr	x12, [x3, #(7 * 8)]
+	ldr	x11, [x3, #(6 * 8)]
+	ldr	x10, [x3, #(5 * 8)]
+	ldr	x9, [x3, #(4 * 8)]
+	ldr	x8, [x3, #(3 * 8)]
+	ldr	x7, [x3, #(2 * 8)]
+	ldr	x6, [x3, #(1 * 8)]
+	ldr	x5, [x3, #(0 * 8)]
+
+	adr	x26, 1f
+	add	x26, x26, x24, lsl #2
+	br	x26
+1:
+	msr	dbgbcr15_el1, x20
+	msr	dbgbcr14_el1, x19
+	msr	dbgbcr13_el1, x18
+	msr	dbgbcr12_el1, x17
+	msr	dbgbcr11_el1, x16
+	msr	dbgbcr10_el1, x15
+	msr	dbgbcr9_el1, x14
+	msr	dbgbcr8_el1, x13
+	msr	dbgbcr7_el1, x12
+	msr	dbgbcr6_el1, x11
+	msr	dbgbcr5_el1, x10
+	msr	dbgbcr4_el1, x9
+	msr	dbgbcr3_el1, x8
+	msr	dbgbcr2_el1, x7
+	msr	dbgbcr1_el1, x6
+	msr	dbgbcr0_el1, x5
+
+	add	x3, x2, #CPU_SYSREG_OFFSET(DBGBVR0_EL1)
+
+	adr	x26, 1f
+	add	x26, x26, x24, lsl #2
+	br	x26
+1:
+	ldr	x20, [x3, #(15 * 8)]
+	ldr	x19, [x3, #(14 * 8)]
+	ldr	x18, [x3, #(13 * 8)]
+	ldr	x17, [x3, #(12 * 8)]
+	ldr	x16, [x3, #(11 * 8)]
+	ldr	x15, [x3, #(10 * 8)]
+	ldr	x14, [x3, #(9 * 8)]
+	ldr	x13, [x3, #(8 * 8)]
+	ldr	x12, [x3, #(7 * 8)]
+	ldr	x11, [x3, #(6 * 8)]
+	ldr	x10, [x3, #(5 * 8)]
+	ldr	x9, [x3, #(4 * 8)]
+	ldr	x8, [x3, #(3 * 8)]
+	ldr	x7, [x3, #(2 * 8)]
+	ldr	x6, [x3, #(1 * 8)]
+	ldr	x5, [x3, #(0 * 8)]
+
+	adr	x26, 1f
+	add	x26, x26, x24, lsl #2
+	br	x26
+1:
+	msr	dbgbvr15_el1, x20
+	msr	dbgbvr14_el1, x19
+	msr	dbgbvr13_el1, x18
+	msr	dbgbvr12_el1, x17
+	msr	dbgbvr11_el1, x16
+	msr	dbgbvr10_el1, x15
+	msr	dbgbvr9_el1, x14
+	msr	dbgbvr8_el1, x13
+	msr	dbgbvr7_el1, x12
+	msr	dbgbvr6_el1, x11
+	msr	dbgbvr5_el1, x10
+	msr	dbgbvr4_el1, x9
+	msr	dbgbvr3_el1, x8
+	msr	dbgbvr2_el1, x7
+	msr	dbgbvr1_el1, x6
+	msr	dbgbvr0_el1, x5
+
+	add	x3, x2, #CPU_SYSREG_OFFSET(DBGWCR0_EL1)
+
+	adr	x26, 1f
+	add	x26, x26, x25, lsl #2
+	br	x26
+1:
+	ldr	x20, [x3, #(15 * 8)]
+	ldr	x19, [x3, #(14 * 8)]
+	ldr	x18, [x3, #(13 * 8)]
+	ldr	x17, [x3, #(12 * 8)]
+	ldr	x16, [x3, #(11 * 8)]
+	ldr	x15, [x3, #(10 * 8)]
+	ldr	x14, [x3, #(9 * 8)]
+	ldr	x13, [x3, #(8 * 8)]
+	ldr	x12, [x3, #(7 * 8)]
+	ldr	x11, [x3, #(6 * 8)]
+	ldr	x10, [x3, #(5 * 8)]
+	ldr	x9, [x3, #(4 * 8)]
+	ldr	x8, [x3, #(3 * 8)]
+	ldr	x7, [x3, #(2 * 8)]
+	ldr	x6, [x3, #(1 * 8)]
+	ldr	x5, [x3, #(0 * 8)]
+
+	adr	x26, 1f
+	add	x26, x26, x25, lsl #2
+	br	x26
+1:
+	msr	dbgwcr15_el1, x20
+	msr	dbgwcr14_el1, x19
+	msr	dbgwcr13_el1, x18
+	msr	dbgwcr12_el1, x17
+	msr	dbgwcr11_el1, x16
+	msr	dbgwcr10_el1, x15
+	msr	dbgwcr9_el1, x14
+	msr	dbgwcr8_el1, x13
+	msr	dbgwcr7_el1, x12
+	msr	dbgwcr6_el1, x11
+	msr	dbgwcr5_el1, x10
+	msr	dbgwcr4_el1, x9
+	msr	dbgwcr3_el1, x8
+	msr	dbgwcr2_el1, x7
+	msr	dbgwcr1_el1, x6
+	msr	dbgwcr0_el1, x5
+
+	add	x3, x2, #CPU_SYSREG_OFFSET(DBGWVR0_EL1)
+
+	adr	x26, 1f
+	add	x26, x26, x25, lsl #2
+	br	x26
+1:
+	ldr	x20, [x3, #(15 * 8)]
+	ldr	x19, [x3, #(14 * 8)]
+	ldr	x18, [x3, #(13 * 8)]
+	ldr	x17, [x3, #(12 * 8)]
+	ldr	x16, [x3, #(11 * 8)]
+	ldr	x15, [x3, #(10 * 8)]
+	ldr	x14, [x3, #(9 * 8)]
+	ldr	x13, [x3, #(8 * 8)]
+	ldr	x12, [x3, #(7 * 8)]
+	ldr	x11, [x3, #(6 * 8)]
+	ldr	x10, [x3, #(5 * 8)]
+	ldr	x9, [x3, #(4 * 8)]
+	ldr	x8, [x3, #(3 * 8)]
+	ldr	x7, [x3, #(2 * 8)]
+	ldr	x6, [x3, #(1 * 8)]
+	ldr	x5, [x3, #(0 * 8)]
+
+	adr	x26, 1f
+	add	x26, x26, x25, lsl #2
+	br	x26
+1:
+	msr	dbgwvr15_el1, x20
+	msr	dbgwvr14_el1, x19
+	msr	dbgwvr13_el1, x18
+	msr	dbgwvr12_el1, x17
+	msr	dbgwvr11_el1, x16
+	msr	dbgwvr10_el1, x15
+	msr	dbgwvr9_el1, x14
+	msr	dbgwvr8_el1, x13
+	msr	dbgwvr7_el1, x12
+	msr	dbgwvr6_el1, x11
+	msr	dbgwvr5_el1, x10
+	msr	dbgwvr4_el1, x9
+	msr	dbgwvr3_el1, x8
+	msr	dbgwvr2_el1, x7
+	msr	dbgwvr1_el1, x6
+	msr	dbgwvr0_el1, x5
+
+	ldr	x21, [x2, #CPU_SYSREG_OFFSET(MDCCINT_EL1)]
+	msr	mdccint_el1, x21
 .endm
 
 .macro skip_32bit_state tmp, target
@@ -282,6 +671,11 @@  __kvm_hyp_code_start:
 	tbz	\tmp, #12, \target
 .endm
 
+.macro skip_clean_debug_state tmp, target
+	ldr	\tmp, [x0, #VCPU_DEBUG_FLAGS]
+	tbz	\tmp, #KVM_ARM64_DEBUG_DIRTY_SHIFT, \target
+.endm
+
 .macro save_guest_32bit_state
 	skip_32bit_state x3, 1f
 
@@ -297,10 +691,13 @@  __kvm_hyp_code_start:
 	mrs	x4, dacr32_el2
 	mrs	x5, ifsr32_el2
 	mrs	x6, fpexc32_el2
-	mrs	x7, dbgvcr32_el2
 	stp	x4, x5, [x3]
-	stp	x6, x7, [x3, #16]
+	str	x6, [x3, #16]
 
+	skip_clean_debug_state x8, 2f
+	mrs	x7, dbgvcr32_el2
+	str	x7, [x3, #24]
+2:
 	skip_tee_state x8, 1f
 
 	add	x3, x2, #CPU_SYSREG_OFFSET(TEECR32_EL1)
@@ -323,12 +720,15 @@  __kvm_hyp_code_start:
 
 	add	x3, x2, #CPU_SYSREG_OFFSET(DACR32_EL2)
 	ldp	x4, x5, [x3]
-	ldp	x6, x7, [x3, #16]
+	ldr	x6, [x3, #16]
 	msr	dacr32_el2, x4
 	msr	ifsr32_el2, x5
 	msr	fpexc32_el2, x6
-	msr	dbgvcr32_el2, x7
 
+	skip_clean_debug_state x8, 2f
+	ldr	x7, [x3, #24]
+	msr	dbgvcr32_el2, x7
+2:
 	skip_tee_state x8, 1f
 
 	add	x3, x2, #CPU_SYSREG_OFFSET(TEECR32_EL1)
@@ -537,6 +937,14 @@  __restore_sysregs:
 	restore_sysregs
 	ret
 
+__save_debug:
+	save_debug
+	ret
+
+__restore_debug:
+	restore_debug
+	ret
+
 __save_fpsimd:
 	save_fpsimd
 	ret
@@ -568,6 +976,21 @@  ENTRY(__kvm_vcpu_run)
 	bl __save_fpsimd
 	bl __save_sysregs
 
+	// Compute debug state: If any of KDE, MDE or KVM_ARM64_DEBUG_DIRTY
+	// is set, we do a full save/restore cycle and disable trapping.
+	add	x25, x0, #VCPU_CONTEXT
+	ldr	x25, [x25, #CPU_SYSREG_OFFSET(MDSCR_EL1)]
+	and	x26, x25, #DBG_MDSCR_KDE
+	and	x25, x25, #DBG_MDSCR_MDE
+	adds	xzr, x25, x26
+	mov	x26, #KVM_ARM64_DEBUG_DIRTY
+	csel	x25, x26, xzr, ne
+	ldr	x26, [x0, #VCPU_DEBUG_FLAGS]
+	orr	x26, x26, x25
+	cbz	x26, 1f
+	str	x26, [x0, #VCPU_DEBUG_FLAGS]
+	bl	__save_debug
+1:
 	activate_traps
 	activate_vm
 
@@ -579,6 +1002,10 @@  ENTRY(__kvm_vcpu_run)
 
 	bl __restore_sysregs
 	bl __restore_fpsimd
+
+	skip_clean_debug_state x3, 1f
+	bl	__restore_debug
+1:
 	restore_guest_32bit_state
 	restore_guest_regs
 
@@ -595,6 +1022,10 @@  __kvm_vcpu_return:
 	save_guest_regs
 	bl __save_fpsimd
 	bl __save_sysregs
+
+	skip_clean_debug_state x3, 1f
+	bl	__save_debug
+1:
 	save_guest_32bit_state
 
 	save_timer_state
@@ -609,6 +1040,12 @@  __kvm_vcpu_return:
 
 	bl __restore_sysregs
 	bl __restore_fpsimd
+
+	skip_clean_debug_state x3, 1f
+	// Clear the dirty flag for the next run
+	str	xzr, [x0, #VCPU_DEBUG_FLAGS]
+	bl	__restore_debug
+1:
 	restore_host_regs
 
 	mov	x0, x1