Hi Tyler,

I know I've had my last comment already ;), but I thought I'd rather
raise the question than stay confused...

Tyler Baicar <tbai...@codeaurora.org> writes:

> Currently external aborts are unsupported by the guest abort
> handling. Add handling for SEAs so that the host kernel reports
> SEAs which occur in the guest kernel.
>
> Signed-off-by: Tyler Baicar <tbai...@codeaurora.org>
> ---
>  arch/arm/include/asm/kvm_arm.h       |  1 +
>  arch/arm/include/asm/system_misc.h   |  5 +++++
>  arch/arm/kvm/mmu.c                   | 15 +++++++++++++--
>  arch/arm64/include/asm/kvm_arm.h     |  1 +
>  arch/arm64/include/asm/system_misc.h |  2 ++
>  arch/arm64/mm/fault.c                | 13 +++++++++++++
>  6 files changed, 35 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
> index e22089f..33a77509 100644
> --- a/arch/arm/include/asm/kvm_arm.h
> +++ b/arch/arm/include/asm/kvm_arm.h
> @@ -187,6 +187,7 @@
>  #define FSC_FAULT    (0x04)
>  #define FSC_ACCESS   (0x08)
>  #define FSC_PERM     (0x0c)
> +#define FSC_EXTABT   (0x10)
>  
>  /* Hyp Prefetch Fault Address Register (HPFAR/HDFAR) */
>  #define HPFAR_MASK   (~0xf)
> diff --git a/arch/arm/include/asm/system_misc.h 
> b/arch/arm/include/asm/system_misc.h
> index a3d61ad..86e1faa 100644
> --- a/arch/arm/include/asm/system_misc.h
> +++ b/arch/arm/include/asm/system_misc.h
> @@ -24,4 +24,9 @@ extern unsigned int user_debug;
>  
>  #endif /* !__ASSEMBLY__ */
>  
> +inline int handle_guest_sea(unsigned long addr, unsigned int esr)
> +{
> +     return -1;
> +}
> +
>  #endif /* __ASM_ARM_SYSTEM_MISC_H */
> diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> index e9a5c0e..24cde84 100644
> --- a/arch/arm/kvm/mmu.c
> +++ b/arch/arm/kvm/mmu.c
> @@ -29,6 +29,7 @@
>  #include <asm/kvm_asm.h>
>  #include <asm/kvm_emulate.h>
>  #include <asm/virt.h>
> +#include <asm/system_misc.h>
>  
>  #include "trace.h"
>  
> @@ -1441,8 +1442,18 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, 
> struct kvm_run *run)
>  
>       /* Check the stage-2 fault is trans. fault or write fault */
>       fault_status = kvm_vcpu_trap_get_fault_type(vcpu);
> -     if (fault_status != FSC_FAULT && fault_status != FSC_PERM &&
> -         fault_status != FSC_ACCESS) {
> +
> +     if (fault_status == FSC_EXTABT) {
> +             if(handle_guest_sea((unsigned long)fault_ipa,
> +                                 kvm_vcpu_get_hsr(vcpu))) {
> +                     kvm_err("Failed to handle guest SEA, FSC: EC=%#x 
> xFSC=%#lx ESR_EL2=%#lx\n",
> +                             kvm_vcpu_trap_get_class(vcpu),
> +                             (unsigned long)kvm_vcpu_trap_get_fault(vcpu),
> +                             (unsigned long)kvm_vcpu_get_hsr(vcpu));
> +                     return -EFAULT;
> +             }
> +     } else if (fault_status != FSC_FAULT && fault_status != FSC_PERM &&
> +                fault_status != FSC_ACCESS) {
>               kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",
>                       kvm_vcpu_trap_get_class(vcpu),
>                       (unsigned long)kvm_vcpu_trap_get_fault(vcpu),
> diff --git a/arch/arm64/include/asm/kvm_arm.h 
> b/arch/arm64/include/asm/kvm_arm.h
> index 4b5c977..be0efb6 100644
> --- a/arch/arm64/include/asm/kvm_arm.h
> +++ b/arch/arm64/include/asm/kvm_arm.h
> @@ -201,6 +201,7 @@
>  #define FSC_FAULT    ESR_ELx_FSC_FAULT
>  #define FSC_ACCESS   ESR_ELx_FSC_ACCESS
>  #define FSC_PERM     ESR_ELx_FSC_PERM
> +#define FSC_EXTABT   ESR_ELx_FSC_EXTABT
>  
>  /* Hyp Prefetch Fault Address Register (HPFAR/HDFAR) */
>  #define HPFAR_MASK   (~UL(0xf))
> diff --git a/arch/arm64/include/asm/system_misc.h 
> b/arch/arm64/include/asm/system_misc.h
> index 90daf4a..8522fff 100644
> --- a/arch/arm64/include/asm/system_misc.h
> +++ b/arch/arm64/include/asm/system_misc.h
> @@ -77,4 +77,6 @@ extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, 
> const char *cmd);
>  int sea_register_handler_chain(struct notifier_block *nb);
>  void sea_unregister_handler_chain(struct notifier_block *nb);
>  
> +int handle_guest_sea(unsigned long addr, unsigned int esr);
> +
>  #endif       /* __ASM_SYSTEM_MISC_H */
> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
> index 81cb7ad..d714432 100644
> --- a/arch/arm64/mm/fault.c
> +++ b/arch/arm64/mm/fault.c
> @@ -597,6 +597,19 @@ static const char *fault_name(unsigned int esr)
>  }
>  
>  /*
> + * Handle Synchronous External Aborts that occur in a guest kernel.
> + */
> +int handle_guest_sea(unsigned long addr, unsigned int esr)
> +{
> +     atomic_notifier_call_chain(&sea_handler_chain, 0, NULL);
> +
> +     pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n",
> +             fault_name(esr), esr, addr);
> +
> +     return 0;
> +}

Don't we need to pass the abort to the guest?

Thanks,
Punit

> +
> +/*
>   * Dispatch a data abort to the relevant handler.
>   */
>  asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int 
> esr,

Reply via email to