[Xen-devel,RFC,11/16] xen/arm: vsysreg: Add wrapper to handle sysreg access trapped by HCR_EL2.TVM

Message ID 20181008183352.16291-12-julien.grall@arm.com
State Accepted
Commit 66f5b576adf89ec8b71084160389e77ff1bb482f
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Series
  • xen/arm: Implement Set/Way operations
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Commit Message

Julien Grall Oct. 8, 2018, 6:33 p.m.
A follow-up patch will require to emulate some accesses to system
registers trapped by HCR_EL2.TVM. When set, all NS EL1 writes to the
virtual memory control registers will be trapped to the hypervisor.

This patch adds the infrastructure to passthrough the access to the host
registers.

Note that HCR_EL2.TVM will be set in a follow-up patch dynamically.

Signed-off-by: Julien Grall <julien.grall@arm.com>
---
 xen/arch/arm/arm64/vsysreg.c | 57 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

Comments

Stefano Stabellini Nov. 5, 2018, 8:42 p.m. | #1
On Mon, 8 Oct 2018, Julien Grall wrote:
> A follow-up patch will require to emulate some accesses to system
> registers trapped by HCR_EL2.TVM. When set, all NS EL1 writes to the
> virtual memory control registers will be trapped to the hypervisor.
> 
> This patch adds the infrastructure to passthrough the access to the host
> registers.
> 
> Note that HCR_EL2.TVM will be set in a follow-up patch dynamically.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>
> ---
>  xen/arch/arm/arm64/vsysreg.c | 57 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 57 insertions(+)
> 
> diff --git a/xen/arch/arm/arm64/vsysreg.c b/xen/arch/arm/arm64/vsysreg.c
> index 6e60824572..1517879697 100644
> --- a/xen/arch/arm/arm64/vsysreg.c
> +++ b/xen/arch/arm/arm64/vsysreg.c
> @@ -23,6 +23,46 @@
>  #include <asm/traps.h>
>  #include <asm/vtimer.h>
>  
> +/*
> + * Macro to help generating helpers for registers trapped when
> + * HCR_EL2.TVM is set.
> + *
> + * Note that it only traps NS write access from EL1.
> + */
> +#define TVM_REG(reg)                                                \
> +static bool vreg_emulate_##reg(struct cpu_user_regs *regs,          \
> +                               uint64_t *r, bool read)              \
> +{                                                                   \
> +    GUEST_BUG_ON(read);                                             \
> +    WRITE_SYSREG64(*r, reg);                                        \
> +                                                                    \
> +    return true;                                                    \
> +}
> +
> +/* Defining helpers for emulating sysreg registers. */
> +TVM_REG(SCTLR_EL1)
> +TVM_REG(TTBR0_EL1)
> +TVM_REG(TTBR1_EL1)
> +TVM_REG(TCR_EL1)
> +TVM_REG(ESR_EL1)
> +TVM_REG(FAR_EL1)
> +TVM_REG(AFSR0_EL1)
> +TVM_REG(AFSR1_EL1)
> +TVM_REG(MAIR_EL1)
> +TVM_REG(AMAIR_EL1)
> +TVM_REG(CONTEXTIDR_EL1)
> +
> +/* Macro to generate easily case for co-processor emulation */
> +#define GENERATE_CASE(reg)                                              \
> +    case HSR_SYSREG_##reg:                                              \
> +    {                                                                   \
> +        bool res;                                                       \
> +                                                                        \
> +        res = vreg_emulate_sysreg64(regs, hsr, vreg_emulate_##reg);     \
> +        ASSERT(res);                                                    \
> +        break;                                                          \
> +    }
> +
>  void do_sysreg(struct cpu_user_regs *regs,
>                 const union hsr hsr)
>  {
> @@ -44,6 +84,23 @@ void do_sysreg(struct cpu_user_regs *regs,
>          break;
>  
>      /*
> +     * HCR_EL2.TVM
> +     *
> +     * ARMv8 (DDI 0487B.b): Table D1-37

You might want to provide a more up to date reference.
In any case:

Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

> +     */
> +    GENERATE_CASE(SCTLR_EL1)
> +    GENERATE_CASE(TTBR0_EL1)
> +    GENERATE_CASE(TTBR1_EL1)
> +    GENERATE_CASE(TCR_EL1)
> +    GENERATE_CASE(ESR_EL1)
> +    GENERATE_CASE(FAR_EL1)
> +    GENERATE_CASE(AFSR0_EL1)
> +    GENERATE_CASE(AFSR1_EL1)
> +    GENERATE_CASE(MAIR_EL1)
> +    GENERATE_CASE(AMAIR_EL1)
> +    GENERATE_CASE(CONTEXTIDR_EL1)
> +
> +    /*
>       * MDCR_EL2.TDRA
>       *
>       * ARMv8 (DDI 0487A.d): D1-1508 Table D1-57
> -- 
> 2.11.0
>

Patch

diff --git a/xen/arch/arm/arm64/vsysreg.c b/xen/arch/arm/arm64/vsysreg.c
index 6e60824572..1517879697 100644
--- a/xen/arch/arm/arm64/vsysreg.c
+++ b/xen/arch/arm/arm64/vsysreg.c
@@ -23,6 +23,46 @@ 
 #include <asm/traps.h>
 #include <asm/vtimer.h>
 
+/*
+ * Macro to help generating helpers for registers trapped when
+ * HCR_EL2.TVM is set.
+ *
+ * Note that it only traps NS write access from EL1.
+ */
+#define TVM_REG(reg)                                                \
+static bool vreg_emulate_##reg(struct cpu_user_regs *regs,          \
+                               uint64_t *r, bool read)              \
+{                                                                   \
+    GUEST_BUG_ON(read);                                             \
+    WRITE_SYSREG64(*r, reg);                                        \
+                                                                    \
+    return true;                                                    \
+}
+
+/* Defining helpers for emulating sysreg registers. */
+TVM_REG(SCTLR_EL1)
+TVM_REG(TTBR0_EL1)
+TVM_REG(TTBR1_EL1)
+TVM_REG(TCR_EL1)
+TVM_REG(ESR_EL1)
+TVM_REG(FAR_EL1)
+TVM_REG(AFSR0_EL1)
+TVM_REG(AFSR1_EL1)
+TVM_REG(MAIR_EL1)
+TVM_REG(AMAIR_EL1)
+TVM_REG(CONTEXTIDR_EL1)
+
+/* Macro to generate easily case for co-processor emulation */
+#define GENERATE_CASE(reg)                                              \
+    case HSR_SYSREG_##reg:                                              \
+    {                                                                   \
+        bool res;                                                       \
+                                                                        \
+        res = vreg_emulate_sysreg64(regs, hsr, vreg_emulate_##reg);     \
+        ASSERT(res);                                                    \
+        break;                                                          \
+    }
+
 void do_sysreg(struct cpu_user_regs *regs,
                const union hsr hsr)
 {
@@ -44,6 +84,23 @@  void do_sysreg(struct cpu_user_regs *regs,
         break;
 
     /*
+     * HCR_EL2.TVM
+     *
+     * ARMv8 (DDI 0487B.b): Table D1-37
+     */
+    GENERATE_CASE(SCTLR_EL1)
+    GENERATE_CASE(TTBR0_EL1)
+    GENERATE_CASE(TTBR1_EL1)
+    GENERATE_CASE(TCR_EL1)
+    GENERATE_CASE(ESR_EL1)
+    GENERATE_CASE(FAR_EL1)
+    GENERATE_CASE(AFSR0_EL1)
+    GENERATE_CASE(AFSR1_EL1)
+    GENERATE_CASE(MAIR_EL1)
+    GENERATE_CASE(AMAIR_EL1)
+    GENERATE_CASE(CONTEXTIDR_EL1)
+
+    /*
      * MDCR_EL2.TDRA
      *
      * ARMv8 (DDI 0487A.d): D1-1508 Table D1-57