[PATCH v4 18/21] KVM: arm64: Handle RAS SErrors from EL1 on guest exit

[Christoffer Dall]

On Thu, Oct 19, 2017 at 03:58:04PM +0100, James Morse wrote:
> We expect to have firmware-first handling of RAS SErrors, with errors
> notified via an APEI method. For systems without firmware-first, add
> some minimal handling to KVM.
> 
> There are two ways KVM can take an SError due to a guest, either may be a
> RAS error: we exit the guest due to an SError routed to EL2 by HCR_EL2.AMO,
> or we take an SError from EL2 when we unmask PSTATE.A from __guest_exit.
> 
> For SError that interrupt a guest and are routed to EL2 the existing
> behaviour is to inject an impdef SError into the guest.
> 
> Add code to handle RAS SError based on the ESR. For uncontained errors
> arm64_is_blocking_ras_serror() will panic(), these errors compromise
> the host too. All other error types are contained: For the 'blocking'
> errors the vCPU can't make progress, so we inject a virtual SError.
> We ignore contained errors where we can make progress as if we're lucky,
> we may not hit them again.
> 
> Signed-off-by: James Morse <james.morse at arm.com>

Reviewed-by: Christoffer Dall <christoffer.dall at linaro.org>

> ---
>  arch/arm64/kvm/handle_exit.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index 7debb74843a0..345fdbba6c2e 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -28,12 +28,19 @@
>  #include <asm/kvm_emulate.h>
>  #include <asm/kvm_mmu.h>
>  #include <asm/kvm_psci.h>
> +#include <asm/traps.h>
>  
>  #define CREATE_TRACE_POINTS
>  #include "trace.h"
>  
>  typedef int (*exit_handle_fn)(struct kvm_vcpu *, struct kvm_run *);
>  
> +static void kvm_handle_guest_serror(struct kvm_vcpu *vcpu, u32 esr)
> +{
> +	if (!arm64_is_ras_serror(esr) || arm64_blocking_ras_serror(NULL, esr))
> +		kvm_inject_vabt(vcpu);
> +}
> +
>  static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run)
>  {
>  	int ret;
> @@ -211,7 +218,7 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
>  	case ARM_EXCEPTION_IRQ:
>  		return 1;
>  	case ARM_EXCEPTION_EL1_SERROR:
> -		kvm_inject_vabt(vcpu);
> +		kvm_handle_guest_serror(vcpu, kvm_vcpu_get_hsr(vcpu));
>  		return 1;
>  	case ARM_EXCEPTION_TRAP:
>  		/*
> -- 
> 2.13.3
>