| Message ID | 1427111639-4575-2-git-send-email-takahiro.akashi@linaro.org |
|---|---|
| State | New |
| Headers | show |
Geoff, On 03/24/2015 01:46 AM, Geoff Levand wrote: > Hi Takahiro, > > On Mon, 2015-03-23 at 20:53 +0900, AKASHI Takahiro wrote: >> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c >> index 3e6859b..428f41c 100644 >> --- a/arch/arm/kvm/mmu.c >> +++ b/arch/arm/kvm/mmu.c > ... >> +phys_addr_t kvm_get_stub_vectors(void) >> +{ >> + return virt_to_phys(__hyp_stub_vectors); >> +} > > The stub vectors are not part of KVM, but part of kernel, > so to me a routine get_hyp_stub_vectors() with a prototype > in asm/virt.h, then a definition in maybe > kernel/process.c, or a new file kernel/virt.c makes more > sense. Right. Will rename the function to get_hyp_stub_vectors() and put it in asm/virt.h. >> +unsigned long kvm_reset_func_entry(void) >> +{ >> + /* VA of __kvm_hyp_reset in trampline code */ >> + return TRAMPOLINE_VA + (__kvm_hyp_reset - __hyp_idmap_text_start); >> +} >> + >> int kvm_mmu_init(void) >> { >> int err; >> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h >> index 4f7310f..97ee2fc 100644 >> --- a/arch/arm64/include/asm/kvm_asm.h >> +++ b/arch/arm64/include/asm/kvm_asm.h >> @@ -116,8 +116,11 @@ >> struct kvm; >> struct kvm_vcpu; >> >> +extern char __hyp_stub_vectors[]; > > I think this should at least be in asm/virt.h, or better, > have a get_hyp_stub_vectors(). See above. >> extern char __kvm_hyp_init[]; >> extern char __kvm_hyp_init_end[]; >> +extern char __kvm_hyp_reset[]; >> >> extern char __kvm_hyp_vector[]; >> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h >> index 8ac3c70..97f88fe 100644 >> --- a/arch/arm64/include/asm/kvm_host.h >> +++ b/arch/arm64/include/asm/kvm_host.h >> @@ -199,6 +199,7 @@ struct kvm_vcpu *kvm_arm_get_running_vcpu(void); >> struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void); >> >> u64 kvm_call_hyp(void *hypfn, ...); >> +void kvm_call_reset(unsigned long reset_func, ...); > > kvm_call_reset() takes a fixed number of args, so we shouldn't > have it as a variadic here. I think a variadic routine > complicates things for my kvm_call_reset() suggestion below. > >> void force_vm_exit(const cpumask_t *mask); >> void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot); >> >> @@ -223,6 +224,15 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr, >> hyp_stack_ptr, vector_ptr); >> } >> >> +static inline void __cpu_reset_hyp_mode(unsigned long reset_func, >> + phys_addr_t boot_pgd_ptr, >> + phys_addr_t phys_idmap_start, >> + unsigned long stub_vector_ptr) > >> + kvm_call_reset(reset_func, boot_pgd_ptr, >> + phys_idmap_start, stub_vector_ptr); > > Why not switch the order of the args here to: > > kvm_call_reset(boot_pgd_ptr, phys_idmap_start, stub_vector_ptr, reset_func) > > This will eliminate the register shifting in the HVC_RESET > hcall vector which becomes just 'br x3'. Looks nice. FYI, initially I wanted to implement kvm_cpu_reset() using kvm_call_hyp() and so both have similar code. > >> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S >> index fd085ec..aee75f9 100644 >> --- a/arch/arm64/kvm/hyp.S >> +++ b/arch/arm64/kvm/hyp.S >> @@ -1136,6 +1136,11 @@ ENTRY(kvm_call_hyp) >> ret >> ENDPROC(kvm_call_hyp) >> >> +ENTRY(kvm_call_reset) >> + hvc #HVC_RESET >> + ret >> +ENDPROC(kvm_call_reset) >> + >> .macro invalid_vector label, target >> .align 2 >> \label: >> @@ -1179,10 +1184,10 @@ el1_sync: // Guest trapped into EL2 >> cmp x18, #HVC_GET_VECTORS >> b.ne 1f >> mrs x0, vbar_el2 >> - b 2f >> - >> -1: /* Default to HVC_CALL_HYP. */ > > It seems you are deleting this comment and also > removing the logic that makes HVC_CALL_HYP the default. Yeah, I didn't think of that. But IIUC, we don't have to handle it as default case because all interfaces come from kvm_call_hyp() once KVM is initialized. >> + b 3f >> >> +1: cmp x18, #HVC_CALL_HYP >> + b.ne 2f >> push lr, xzr >> >> /* >> @@ -1196,7 +1201,23 @@ el1_sync: // Guest trapped into EL2 >> blr lr >> >> pop lr, xzr >> -2: eret >> + b 3f >> + >> + /* >> + * shuffle the parameters and jump into trampline code. >> + */ >> +2: cmp x18, #HVC_RESET >> + b.ne 3f >> + >> + mov x18, x0 >> + mov x0, x1 >> + mov x1, x2 >> + mov x2, x3 >> + mov x3, x4 >> + br x18 >> + /* not reach here */ >> + >> +3: eret > > We don't need to change labels for each new hcall, I > think just this is OK: > > cmp x18, #HVC_GET_VECTORS > b.ne 1f > mrs x0, vbar_el2 > b 2f > > +1: cmp x18, #HVC_RESET > + b.ne 1f > + br x3 // No return > > 1: /* Default to HVC_CALL_HYP. */ > ... Will fix it. Thanks, -Takahiro AKASHI > -Geoff > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Marc, On 03/24/2015 07:00 PM, Marc Zyngier wrote: > Hi Takahiro, > > On 23/03/15 11:53, AKASHI Takahiro wrote: >> Cpu must be put back into its initial state, at least, in the >> following cases in order to shutdown the system and/or re-initialize cpus >> later on: >> 1) kexec/kdump >> 2) cpu hotplug (offline) >> 3) removing kvm as a module >> >> To address those issues in later patches, this patch adds a tear-down >> function, kvm_cpu_reset(), that disables D-cache & MMU and restore a vector >> table to the initial stub at EL2. > > Thanks for having a look at this. > >> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> >> --- >> arch/arm/kvm/arm.c | 18 ++++++++++++++++ >> arch/arm/kvm/mmu.c | 16 +++++++++++++++ >> arch/arm64/include/asm/kvm_asm.h | 3 +++ >> arch/arm64/include/asm/kvm_host.h | 10 +++++++++ >> arch/arm64/include/asm/kvm_mmu.h | 3 +++ >> arch/arm64/include/asm/virt.h | 11 ++++++++++ >> arch/arm64/kvm/hyp-init.S | 41 +++++++++++++++++++++++++++++++++++++ >> arch/arm64/kvm/hyp.S | 29 ++++++++++++++++++++++---- >> 8 files changed, 127 insertions(+), 4 deletions(-) >> >> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c >> index 5560f74..35c8bc0 100644 >> --- a/arch/arm/kvm/arm.c >> +++ b/arch/arm/kvm/arm.c >> @@ -897,6 +897,24 @@ static void cpu_init_hyp_mode(void *dummy) >> __cpu_init_hyp_mode(boot_pgd_ptr, pgd_ptr, hyp_stack_ptr, vector_ptr); >> } >> >> +void kvm_cpu_reset(void *dummy) > > Given that the notifier introduced in patch #2 lives in the same file, > this could be made static, couldn't it? Yes. Will fix it. >> +{ >> + phys_addr_t boot_pgd_ptr; >> + phys_addr_t phys_idmap_start; >> + unsigned long reset_func; >> + unsigned long vector_ptr; >> + >> + if (__hyp_get_vectors() == hyp_default_vectors) >> + return; >> + >> + reset_func = kvm_reset_func_entry(); >> + boot_pgd_ptr = kvm_mmu_get_boot_httbr(); >> + phys_idmap_start = kvm_get_idmap_start(); >> + vector_ptr = kvm_get_stub_vectors(); > > Isn't that hyp_default_vectors already? Yeah, I already use it in kvm_cpu_reset(). Will fix it. >> + __cpu_reset_hyp_mode(reset_func, >> + boot_pgd_ptr, phys_idmap_start, vector_ptr); >> +} >> + >> static int hyp_init_cpu_notify(struct notifier_block *self, >> unsigned long action, void *cpu) >> { >> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c >> index 3e6859b..428f41c 100644 >> --- a/arch/arm/kvm/mmu.c >> +++ b/arch/arm/kvm/mmu.c >> @@ -1490,6 +1490,22 @@ phys_addr_t kvm_get_idmap_vector(void) >> return hyp_idmap_vector; >> } >> >> +phys_addr_t kvm_get_idmap_start(void) >> +{ >> + return hyp_idmap_start; >> +} >> + >> +phys_addr_t kvm_get_stub_vectors(void) >> +{ >> + return virt_to_phys(__hyp_stub_vectors); >> +} > > As Geoff already mentioned, this doesn't belong in KVM. But I don't > think you need it, as explained above. Will remove it. >> + >> +unsigned long kvm_reset_func_entry(void) >> +{ >> + /* VA of __kvm_hyp_reset in trampline code */ >> + return TRAMPOLINE_VA + (__kvm_hyp_reset - __hyp_idmap_text_start); >> +} > > If you need to compute addresses in the trampoline page, it would be > better to have a generic macro that takes a kernel VA, and turns it into > a trampoline VA. This is the only place to calculate the address. But will fix it. >> + >> int kvm_mmu_init(void) >> { >> int err; >> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h >> index 4f7310f..97ee2fc 100644 >> --- a/arch/arm64/include/asm/kvm_asm.h >> +++ b/arch/arm64/include/asm/kvm_asm.h >> @@ -116,8 +116,11 @@ >> struct kvm; >> struct kvm_vcpu; >> >> +extern char __hyp_stub_vectors[]; > > Not a KVM thing (for the same reason). Will remove it. >> + >> extern char __kvm_hyp_init[]; >> extern char __kvm_hyp_init_end[]; >> +extern char __kvm_hyp_reset[]; >> >> extern char __kvm_hyp_vector[]; >> >> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h >> index 8ac3c70..97f88fe 100644 >> --- a/arch/arm64/include/asm/kvm_host.h >> +++ b/arch/arm64/include/asm/kvm_host.h >> @@ -199,6 +199,7 @@ struct kvm_vcpu *kvm_arm_get_running_vcpu(void); >> struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void); >> >> u64 kvm_call_hyp(void *hypfn, ...); >> +void kvm_call_reset(unsigned long reset_func, ...); > > You seem to have a single call signature for this function, and have > defined all the parameters below. You can drop the variadic aspect. As Geoff suggested, the arguments of __cpu_reset_hyp_mode() and kvm_call_reset() will be shuffled as in this order: phys_addr_t boot_pgd_ptr, phys_addr_t phys_idmap_start, unsigned long stub_vector_ptr unsigned long reset_func. >> void force_vm_exit(const cpumask_t *mask); >> void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot); >> >> @@ -223,6 +224,15 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr, >> hyp_stack_ptr, vector_ptr); >> } >> >> +static inline void __cpu_reset_hyp_mode(unsigned long reset_func, >> + phys_addr_t boot_pgd_ptr, >> + phys_addr_t phys_idmap_start, >> + unsigned long stub_vector_ptr) >> +{ >> + kvm_call_reset(reset_func, boot_pgd_ptr, >> + phys_idmap_start, stub_vector_ptr); >> +} >> + >> struct vgic_sr_vectors { >> void *save_vgic; >> void *restore_vgic; >> diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h >> index 6458b53..36be582 100644 >> --- a/arch/arm64/include/asm/kvm_mmu.h >> +++ b/arch/arm64/include/asm/kvm_mmu.h >> @@ -96,6 +96,9 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu); >> phys_addr_t kvm_mmu_get_httbr(void); >> phys_addr_t kvm_mmu_get_boot_httbr(void); >> phys_addr_t kvm_get_idmap_vector(void); >> +phys_addr_t kvm_get_idmap_start(void); >> +phys_addr_t kvm_get_stub_vectors(void); >> +unsigned long kvm_reset_func_entry(void); >> int kvm_mmu_init(void); >> void kvm_clear_hyp_idmap(void); >> >> diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h >> index 3070096..7fcd087 100644 >> --- a/arch/arm64/include/asm/virt.h >> +++ b/arch/arm64/include/asm/virt.h >> @@ -61,6 +61,17 @@ >> #define BOOT_CPU_MODE_EL1 (0xe11) >> #define BOOT_CPU_MODE_EL2 (0xe12) >> >> +/* >> + * HVC_RESET - Reset cpu in EL2 to initial state. >> + * >> + * @x0: entry address in trampoline code in va >> + * @x1: identical mapping page table in pa >> + * @x2: start address of identical mapping in pa >> + * @x3: initial stub vector in pa >> + */ >> + >> +#define HVC_RESET 5 >> + >> #ifndef __ASSEMBLY__ >> >> /* >> diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S >> index c319116..ca7e6bf 100644 >> --- a/arch/arm64/kvm/hyp-init.S >> +++ b/arch/arm64/kvm/hyp-init.S >> @@ -115,6 +115,47 @@ target: /* We're now in the trampoline code, switch page tables */ >> eret >> ENDPROC(__kvm_hyp_init) >> >> + /* >> + * x0: HYP boot pgd >> + * x1: HYP phys_idmap_start >> + * x2: HYP stub vectors >> + */ >> +ENTRY(__kvm_hyp_reset) >> + /* We're in trampoline code in VA */ >> + /* Invalidate the old TLBs */ >> + tlbi alle2 >> + dsb sy > > Invalidating the TLBs before switching TTBR0_EL2 is unlikely to have the > effect you want. > >> + /* Switch back to boot page tables */ >> + msr ttbr0_el2, x0 >> + isb > > This is the place where you want TLBI to occur. Will remove tlbi above and put it here. >> + /* Branch into PA space */ >> + adr x0, 1f >> + bfi x1, x0, #0, #PAGE_SHIFT >> + br x1 >> + >> + /* We're now in idmap */ >> +1: /* Invalidate the old TLBs again */ >> + tlbi alle2 >> + dsb sy > > See? This is the only TLBI that actually makes sense. Now, given that > you are actually disabling the MMU, I'm not sure these TBLIs make much > sense. Probably you're right, but otherwise, I guess, bogus TLB might remain and be used when MMU get enabled again. (MMU setting would be the same across disabling/enabling hyp mode though.) >> + /* Disable MMU */ >> + mrs x0, sctlr_el2 >> + and x1, x0, #SCTLR_EL2_EE >> + orr x0, x0, x1 // preserve endianness of EL2 >> + ldr x1, =SCTLR_EL2_FLAGS >> + eor x1, x1, xzr >> + bic x0, x0, x1 // Clear SCTL_M and etc >> + msr sctlr_el2, x0 >> + isb >> + >> + /* Switch back to stub vectors */ >> + msr vbar_el2, x2 >> + >> + eret >> +ENDPROC(__kvm_hyp_reset) >> + >> .ltorg >> >> .popsection >> diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S >> index fd085ec..aee75f9 100644 >> --- a/arch/arm64/kvm/hyp.S >> +++ b/arch/arm64/kvm/hyp.S >> @@ -1136,6 +1136,11 @@ ENTRY(kvm_call_hyp) >> ret >> ENDPROC(kvm_call_hyp) >> >> +ENTRY(kvm_call_reset) >> + hvc #HVC_RESET >> + ret >> +ENDPROC(kvm_call_reset) >> + >> .macro invalid_vector label, target >> .align 2 >> \label: >> @@ -1179,10 +1184,10 @@ el1_sync: // Guest trapped into EL2 >> cmp x18, #HVC_GET_VECTORS >> b.ne 1f >> mrs x0, vbar_el2 >> - b 2f >> - >> -1: /* Default to HVC_CALL_HYP. */ >> + b 3f >> >> +1: cmp x18, #HVC_CALL_HYP >> + b.ne 2f >> push lr, xzr >> >> /* >> @@ -1196,7 +1201,23 @@ el1_sync: // Guest trapped into EL2 >> blr lr >> >> pop lr, xzr >> -2: eret >> + b 3f >> + >> + /* >> + * shuffle the parameters and jump into trampline code. >> + */ >> +2: cmp x18, #HVC_RESET >> + b.ne 3f >> + >> + mov x18, x0 >> + mov x0, x1 >> + mov x1, x2 >> + mov x2, x3 >> + mov x3, x4 >> + br x18 > > I'd rather move the shuffling of the registers before the HVC call. See above. Thanks, -Takahiro AKASHI >> + /* not reach here */ >> + >> +3: eret >> >> el1_trap: >> /* >> > > Thanks, > > M. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 5560f74..35c8bc0 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -897,6 +897,24 @@ static void cpu_init_hyp_mode(void *dummy) __cpu_init_hyp_mode(boot_pgd_ptr, pgd_ptr, hyp_stack_ptr, vector_ptr); } +void kvm_cpu_reset(void *dummy) +{ + phys_addr_t boot_pgd_ptr; + phys_addr_t phys_idmap_start; + unsigned long reset_func; + unsigned long vector_ptr; + + if (__hyp_get_vectors() == hyp_default_vectors) + return; + + reset_func = kvm_reset_func_entry(); + boot_pgd_ptr = kvm_mmu_get_boot_httbr(); + phys_idmap_start = kvm_get_idmap_start(); + vector_ptr = kvm_get_stub_vectors(); + __cpu_reset_hyp_mode(reset_func, + boot_pgd_ptr, phys_idmap_start, vector_ptr); +} + static int hyp_init_cpu_notify(struct notifier_block *self, unsigned long action, void *cpu) { diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 3e6859b..428f41c 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -1490,6 +1490,22 @@ phys_addr_t kvm_get_idmap_vector(void) return hyp_idmap_vector; } +phys_addr_t kvm_get_idmap_start(void) +{ + return hyp_idmap_start; +} + +phys_addr_t kvm_get_stub_vectors(void) +{ + return virt_to_phys(__hyp_stub_vectors); +} + +unsigned long kvm_reset_func_entry(void) +{ + /* VA of __kvm_hyp_reset in trampline code */ + return TRAMPOLINE_VA + (__kvm_hyp_reset - __hyp_idmap_text_start); +} + int kvm_mmu_init(void) { int err; diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 4f7310f..97ee2fc 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -116,8 +116,11 @@ struct kvm; struct kvm_vcpu; +extern char __hyp_stub_vectors[]; + extern char __kvm_hyp_init[]; extern char __kvm_hyp_init_end[]; +extern char __kvm_hyp_reset[]; extern char __kvm_hyp_vector[]; diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 8ac3c70..97f88fe 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -199,6 +199,7 @@ struct kvm_vcpu *kvm_arm_get_running_vcpu(void); struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void); u64 kvm_call_hyp(void *hypfn, ...); +void kvm_call_reset(unsigned long reset_func, ...); void force_vm_exit(const cpumask_t *mask); void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot); @@ -223,6 +224,15 @@ static inline void __cpu_init_hyp_mode(phys_addr_t boot_pgd_ptr, hyp_stack_ptr, vector_ptr); } +static inline void __cpu_reset_hyp_mode(unsigned long reset_func, + phys_addr_t boot_pgd_ptr, + phys_addr_t phys_idmap_start, + unsigned long stub_vector_ptr) +{ + kvm_call_reset(reset_func, boot_pgd_ptr, + phys_idmap_start, stub_vector_ptr); +} + struct vgic_sr_vectors { void *save_vgic; void *restore_vgic; diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 6458b53..36be582 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -96,6 +96,9 @@ void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu); phys_addr_t kvm_mmu_get_httbr(void); phys_addr_t kvm_mmu_get_boot_httbr(void); phys_addr_t kvm_get_idmap_vector(void); +phys_addr_t kvm_get_idmap_start(void); +phys_addr_t kvm_get_stub_vectors(void); +unsigned long kvm_reset_func_entry(void); int kvm_mmu_init(void); void kvm_clear_hyp_idmap(void); diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index 3070096..7fcd087 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -61,6 +61,17 @@ #define BOOT_CPU_MODE_EL1 (0xe11) #define BOOT_CPU_MODE_EL2 (0xe12) +/* + * HVC_RESET - Reset cpu in EL2 to initial state. + * + * @x0: entry address in trampoline code in va + * @x1: identical mapping page table in pa + * @x2: start address of identical mapping in pa + * @x3: initial stub vector in pa + */ + +#define HVC_RESET 5 + #ifndef __ASSEMBLY__ /* diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S index c319116..ca7e6bf 100644 --- a/arch/arm64/kvm/hyp-init.S +++ b/arch/arm64/kvm/hyp-init.S @@ -115,6 +115,47 @@ target: /* We're now in the trampoline code, switch page tables */ eret ENDPROC(__kvm_hyp_init) + /* + * x0: HYP boot pgd + * x1: HYP phys_idmap_start + * x2: HYP stub vectors + */ +ENTRY(__kvm_hyp_reset) + /* We're in trampoline code in VA */ + /* Invalidate the old TLBs */ + tlbi alle2 + dsb sy + + /* Switch back to boot page tables */ + msr ttbr0_el2, x0 + isb + + /* Branch into PA space */ + adr x0, 1f + bfi x1, x0, #0, #PAGE_SHIFT + br x1 + + /* We're now in idmap */ +1: /* Invalidate the old TLBs again */ + tlbi alle2 + dsb sy + + /* Disable MMU */ + mrs x0, sctlr_el2 + and x1, x0, #SCTLR_EL2_EE + orr x0, x0, x1 // preserve endianness of EL2 + ldr x1, =SCTLR_EL2_FLAGS + eor x1, x1, xzr + bic x0, x0, x1 // Clear SCTL_M and etc + msr sctlr_el2, x0 + isb + + /* Switch back to stub vectors */ + msr vbar_el2, x2 + + eret +ENDPROC(__kvm_hyp_reset) + .ltorg .popsection diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index fd085ec..aee75f9 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -1136,6 +1136,11 @@ ENTRY(kvm_call_hyp) ret ENDPROC(kvm_call_hyp) +ENTRY(kvm_call_reset) + hvc #HVC_RESET + ret +ENDPROC(kvm_call_reset) + .macro invalid_vector label, target .align 2 \label: @@ -1179,10 +1184,10 @@ el1_sync: // Guest trapped into EL2 cmp x18, #HVC_GET_VECTORS b.ne 1f mrs x0, vbar_el2 - b 2f - -1: /* Default to HVC_CALL_HYP. */ + b 3f +1: cmp x18, #HVC_CALL_HYP + b.ne 2f push lr, xzr /* @@ -1196,7 +1201,23 @@ el1_sync: // Guest trapped into EL2 blr lr pop lr, xzr -2: eret + b 3f + + /* + * shuffle the parameters and jump into trampline code. + */ +2: cmp x18, #HVC_RESET + b.ne 3f + + mov x18, x0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + mov x3, x4 + br x18 + /* not reach here */ + +3: eret el1_trap: /*
Cpu must be put back into its initial state, at least, in the following cases in order to shutdown the system and/or re-initialize cpus later on: 1) kexec/kdump 2) cpu hotplug (offline) 3) removing kvm as a module To address those issues in later patches, this patch adds a tear-down function, kvm_cpu_reset(), that disables D-cache & MMU and restore a vector table to the initial stub at EL2. Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> --- arch/arm/kvm/arm.c | 18 ++++++++++++++++ arch/arm/kvm/mmu.c | 16 +++++++++++++++ arch/arm64/include/asm/kvm_asm.h | 3 +++ arch/arm64/include/asm/kvm_host.h | 10 +++++++++ arch/arm64/include/asm/kvm_mmu.h | 3 +++ arch/arm64/include/asm/virt.h | 11 ++++++++++ arch/arm64/kvm/hyp-init.S | 41 +++++++++++++++++++++++++++++++++++++ arch/arm64/kvm/hyp.S | 29 ++++++++++++++++++++++---- 8 files changed, 127 insertions(+), 4 deletions(-)