Messages in this thread | | | Date | Thu, 16 Nov 2023 19:27:10 +0000 | Subject | Re: [PATCH v3 3/6] arm64: KVM: Add iflag for FEAT_TRF | From | Suzuki K Poulose <> |
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On 19/10/2023 17:55, James Clark wrote: > Add an extra iflag to signify if the TRFCR register is accessible. > Because TRBE requires FEAT_TRF, DEBUG_STATE_SAVE_TRBE still has the same > behavior even though it's only set when FEAT_TRF is present. > > The following holes are left in struct kvm_vcpu_arch, but there aren't > enough other 8 bit fields to rearrange it to leave any hole smaller than > 7 bytes: > > u8 cflags; /* 2292 1 */ > /* XXX 1 byte hole, try to pack */ > u16 iflags; /* 2294 2 */ > u8 sflags; /* 2296 1 */ > bool pause; /* 2297 1 */ > /* XXX 6 bytes hole, try to pack */ > > Signed-off-by: James Clark <james.clark@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> --- > arch/arm64/include/asm/kvm_host.h | 4 +++- > arch/arm64/kvm/debug.c | 22 ++++++++++++++++++---- > 2 files changed, 21 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 7c82927ddaf2..0f0bf8e641bd 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -535,7 +535,7 @@ struct kvm_vcpu_arch { > u8 cflags; > > /* Input flags to the hypervisor code, potentially cleared after use */ > - u8 iflags; > + u16 iflags; > > /* State flags for kernel bookkeeping, unused by the hypervisor code */ > u8 sflags; > @@ -741,6 +741,8 @@ struct kvm_vcpu_arch { > #define DEBUG_STATE_SAVE_TRBE __vcpu_single_flag(iflags, BIT(6)) > /* vcpu running in HYP context */ > #define VCPU_HYP_CONTEXT __vcpu_single_flag(iflags, BIT(7)) > +/* Save trace filter controls */ > +#define DEBUG_STATE_SAVE_TRFCR __vcpu_single_flag(iflags, BIT(8)) > > /* SVE enabled for host EL0 */ > #define HOST_SVE_ENABLED __vcpu_single_flag(sflags, BIT(0)) > diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c > index 8725291cb00a..20cdd40b3c42 100644 > --- a/arch/arm64/kvm/debug.c > +++ b/arch/arm64/kvm/debug.c > @@ -331,14 +331,28 @@ void kvm_arch_vcpu_load_debug_state_flags(struct kvm_vcpu *vcpu) > !(read_sysreg_s(SYS_PMBIDR_EL1) & BIT(PMBIDR_EL1_P_SHIFT))) > vcpu_set_flag(vcpu, DEBUG_STATE_SAVE_SPE); > > - /* Check if we have TRBE implemented and available at the host */ > - if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceBuffer_SHIFT) && > - !(read_sysreg_s(SYS_TRBIDR_EL1) & TRBIDR_EL1_P)) > - vcpu_set_flag(vcpu, DEBUG_STATE_SAVE_TRBE); > + /* > + * Save TRFCR on nVHE if FEAT_TRF (TraceFilt) exists. This will be > + * done in cases where use of TRBE doesn't completely disable trace and > + * handles the exclude_host/exclude_guest rules of the trace session. > + */ > + if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceFilt_SHIFT)) { > + vcpu_set_flag(vcpu, DEBUG_STATE_SAVE_TRFCR); > + /* > + * Check if we have TRBE implemented and available at the host. If it's > + * in use at the time of guest switch it will need to be disabled and > + * then restored. The architecture mandates FEAT_TRF with TRBE, so we > + * only need to check for TRBE after TRF. > + */ > + if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceBuffer_SHIFT) && > + !(read_sysreg_s(SYS_TRBIDR_EL1) & TRBIDR_EL1_P)) > + vcpu_set_flag(vcpu, DEBUG_STATE_SAVE_TRBE); > + } > } > > void kvm_arch_vcpu_put_debug_state_flags(struct kvm_vcpu *vcpu) > { > vcpu_clear_flag(vcpu, DEBUG_STATE_SAVE_SPE); > vcpu_clear_flag(vcpu, DEBUG_STATE_SAVE_TRBE); > + vcpu_clear_flag(vcpu, DEBUG_STATE_SAVE_TRFCR); > }
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