ZCR_EL2 controls the upper bound for ZCR_EL1, and is set to a potentially lower limit when the guest uses SVE.
In order to restore the SVE state on the EL1 host, we must first reset ZCR_EL2 to its original value. Provide a hypervall that perform this reset. Signed-off-by: Marc Zyngier <[email protected]> --- arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/include/asm/kvm_host.h | 4 +++- arch/arm64/kvm/hyp/nvhe/hyp-main.c | 8 ++++++++ 3 files changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 22d933e9b59e..7ae947934ec9 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -57,6 +57,7 @@ #define __KVM_HOST_SMCCC_FUNC___kvm_get_mdcr_el2 12 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_save_aprs 13 #define __KVM_HOST_SMCCC_FUNC___vgic_v3_restore_aprs 14 +#define __KVM_HOST_SMCCC_FUNC___kvm_reset_sve_vq 15 #ifndef __ASSEMBLY__ diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index c4afe3d3397f..9108ccc80653 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -593,7 +593,9 @@ int kvm_test_age_hva(struct kvm *kvm, unsigned long hva); void kvm_arm_halt_guest(struct kvm *kvm); void kvm_arm_resume_guest(struct kvm *kvm); -#define kvm_call_hyp_nvhe(f, ...) \ +static inline void __kvm_reset_sve_vq(void) {} + +#define kvm_call_hyp_nvhe(f, ...) \ ({ \ struct arm_smccc_res res; \ \ diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index f012f8665ecc..9fdd8d6e3554 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -106,6 +106,13 @@ static void handle___vgic_v3_restore_aprs(struct kvm_cpu_context *host_ctxt) __vgic_v3_restore_aprs(kern_hyp_va(cpu_if)); } +static void handle___kvm_reset_sve_vq(struct kvm_cpu_context *host_ctxt) +{ + if (system_supports_sve() && + read_sysreg_s(SYS_ZCR_EL2) != ZCR_ELx_LEN_MASK) + write_sysreg_s(ZCR_ELx_LEN_MASK, SYS_ZCR_EL2); +} + typedef void (*hcall_t)(struct kvm_cpu_context *); #define HANDLE_FUNC(x) [__KVM_HOST_SMCCC_FUNC_##x] = (hcall_t)handle_##x @@ -125,6 +132,7 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__kvm_get_mdcr_el2), HANDLE_FUNC(__vgic_v3_save_aprs), HANDLE_FUNC(__vgic_v3_restore_aprs), + HANDLE_FUNC(__kvm_reset_sve_vq), }; static void handle_host_hcall(struct kvm_cpu_context *host_ctxt) -- 2.29.2 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
