On Sun, Apr 30, 2017 at 01:37:56PM +0800, Dongjiu Geng wrote:
> when SError happen, kvm notifies kvmtool to generate GHES table
> to record the error, then kvmtools inject the SError with specified
again, is this really specific to kvmtool? Pleae try to explain this
mechanism in generic terms.
> virtual syndrome. when switch to guest, a virtual SError will happen with
> this specified syndrome.
>
> Signed-off-by: Dongjiu Geng <gengdongjiu@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/esr.h | 2 ++
> arch/arm64/include/asm/kvm_emulate.h | 10 ++++++++++
> arch/arm64/include/asm/kvm_host.h | 1 +
> arch/arm64/include/asm/sysreg.h | 3 +++
> arch/arm64/kvm/handle_exit.c | 25 +++++++++++++++++++------
> arch/arm64/kvm/hyp/switch.c | 15 ++++++++++++++-
> include/uapi/linux/kvm.h | 5 +++++
> 7 files changed, 54 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
> index 22f9c90..d009c99 100644
> --- a/arch/arm64/include/asm/esr.h
> +++ b/arch/arm64/include/asm/esr.h
> @@ -127,6 +127,8 @@
> #define ESR_ELx_WFx_ISS_WFE (UL(1) << 0)
> #define ESR_ELx_xVC_IMM_MASK ((1UL << 16) - 1)
>
> +#define VSESR_ELx_IDS_ISS_MASK ((1UL << 25) - 1)
> +
> /* ESR value templates for specific events */
>
> /* BRK instruction trap from AArch64 state */
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index f5ea0ba..a3259a9 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -148,6 +148,16 @@ static inline u32 kvm_vcpu_get_hsr(const struct kvm_vcpu *vcpu)
> return vcpu->arch.fault.esr_el2;
> }
>
> +static inline u32 kvm_vcpu_get_vsesr(const struct kvm_vcpu *vcpu)
> +{
> + return vcpu->arch.fault.vsesr_el2;
> +}
> +
> +static inline void kvm_vcpu_set_vsesr(struct kvm_vcpu *vcpu, unsigned long val)
> +{
> + vcpu->arch.fault.vsesr_el2 = val;
> +}
> +
> static inline int kvm_vcpu_get_condition(const struct kvm_vcpu *vcpu)
> {
> u32 esr = kvm_vcpu_get_hsr(vcpu);
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index e7705e7..84ed239 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -86,6 +86,7 @@ struct kvm_vcpu_fault_info {
> u32 esr_el2; /* Hyp Syndrom Register */
> u64 far_el2; /* Hyp Fault Address Register */
> u64 hpfar_el2; /* Hyp IPA Fault Address Register */
> + u32 vsesr_el2; /* Virtual SError Exception Syndrome Register */
> };
>
> /*
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index 32964c7..b6afb7a 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -125,6 +125,9 @@
> #define REG_PSTATE_PAN_IMM sys_reg(0, 0, 4, 0, 4)
> #define REG_PSTATE_UAO_IMM sys_reg(0, 0, 4, 0, 3)
>
> +#define VSESR_EL2 sys_reg(3, 4, 5, 2, 3)
> +
> +
> #define SET_PSTATE_PAN(x) __emit_inst(0xd5000000 | REG_PSTATE_PAN_IMM | \
> (!!x)<<8 | 0x1f)
> #define SET_PSTATE_UAO(x) __emit_inst(0xd5000000 | REG_PSTATE_UAO_IMM | \
> diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
> index c89d83a..3d024a9 100644
> --- a/arch/arm64/kvm/handle_exit.c
> +++ b/arch/arm64/kvm/handle_exit.c
> @@ -180,7 +180,11 @@ static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)
>
> static int kvm_handle_guest_sei(struct kvm_vcpu *vcpu, struct kvm_run *run)
> {
> - unsigned long fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
> + unsigned long hva, fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
> + struct kvm_memory_slot *memslot;
> + int hsr, ret = 1;
> + bool writable;
> + gfn_t gfn;
>
> if (handle_guest_sei((unsigned long)fault_ipa,
> kvm_vcpu_get_hsr(vcpu))) {
> @@ -190,9 +194,20 @@ static int kvm_handle_guest_sei(struct kvm_vcpu *vcpu, struct kvm_run *run)
> (unsigned long)kvm_vcpu_get_hsr(vcpu));
>
> kvm_inject_vabt(vcpu);
> + } else {
> + hsr = kvm_vcpu_get_hsr(vcpu);
> +
> + gfn = fault_ipa >> PAGE_SHIFT;
> + memslot = gfn_to_memslot(vcpu->kvm, gfn);
> + hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
> +
> + run->exit_reason = KVM_EXIT_INTR;
> + run->intr.syndrome_info = hsr;
> + run->intr.address = hva;
> + ret = 0;
> }
>
> - return 0;
> + return ret;
> }
>
> /*
> @@ -218,8 +233,7 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
> *vcpu_pc(vcpu) -= adj;
> }
>
> - kvm_handle_guest_sei(vcpu, run);
> - return 1;
> + return kvm_handle_guest_sei(vcpu, run);
> }
>
> exception_index = ARM_EXCEPTION_CODE(exception_index);
> @@ -228,8 +242,7 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
> case ARM_EXCEPTION_IRQ:
> return 1;
> case ARM_EXCEPTION_EL1_SERROR:
> - kvm_handle_guest_sei(vcpu, run);
> - return 1;
> + return kvm_handle_guest_sei(vcpu, run);
> case ARM_EXCEPTION_TRAP:
> /*
> * See ARM ARM B1.14.1: "Hyp traps on instructions
> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
> index aede165..ded6211 100644
> --- a/arch/arm64/kvm/hyp/switch.c
> +++ b/arch/arm64/kvm/hyp/switch.c
> @@ -86,6 +86,13 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
> isb();
> }
> write_sysreg(val, hcr_el2);
> + /* If virtual System Error or Asynchronous Abort is pending. set
nit: I think you want a comma after pending, not a dot.
> + * the virtual exception syndrome information
> + */
nit: commenting style
> + if (cpus_have_cap(ARM64_HAS_RAS_EXTN) &&
> + (vcpu->arch.hcr_el2 & HCR_VSE))
> + write_sysreg_s(vcpu->arch.fault.vsesr_el2, VSESR_EL2);
> +
> /* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
> write_sysreg(1 << 15, hstr_el2);
> /*
> @@ -139,9 +146,15 @@ static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
> * the crucial bit is "On taking a vSError interrupt,
> * HCR_EL2.VSE is cleared to 0."
> */
> - if (vcpu->arch.hcr_el2 & HCR_VSE)
> + if (vcpu->arch.hcr_el2 & HCR_VSE) {
> vcpu->arch.hcr_el2 = read_sysreg(hcr_el2);
>
> + if (cpus_have_cap(ARM64_HAS_RAS_EXTN)) {
> + /* set vsesr_el2[24:0] with esr_el2[24:0] */
> + kvm_vcpu_set_vsesr(vcpu, read_sysreg_el2(esr)
> + & VSESR_ELx_IDS_ISS_MASK);
> + }
> + }
> __deactivate_traps_arch()();
> write_sysreg(0, hstr_el2);
> write_sysreg(0, pmuserenr_el0);
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 27fe556..bb02909 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -360,6 +360,11 @@ struct kvm_run {
> struct {
> __u8 vector;
> } eoi;
> + /* KVM_EXIT_INTR */
> + struct {
> + __u32 syndrome_info;
> + __u64 address;
> + } intr;
definitely, not. KVM_EXIT_INTR is a generic exit code to tell userspace
that we exited because we needed to deliver a signal or something else
related to an asynchronous event. This implies that the syndrome_info
etc. always has valid values on all architectures when exiting with
KVM_EXIT_INTR.
Either document the behavior as the syndrome_info has side-channel
information on every exit, or on some KVM_EXIT_INTR exits, as we explain
in the KVM_CAP_ARM_USER_IRQ ABI that was just added, or dedicate an
access code.
> /* KVM_EXIT_HYPERV */
> struct kvm_hyperv_exit hyperv;
> /* Fix the size of the union. */
> --
> 2.10.1
>
I'll look at the details of such patches once the ABI is clear and
well-documented.
Thanks,
-Christoffer
