[PATCH 03/10] KVM: arm64: switch HCRX_EL2 between host and guest
From: Kristina Martsenko <hidden>
Date: 2023-02-16 16:01:47
Also in:
kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
Switch the HCRX_EL2 register between host and guest configurations, in order to enable different features in the host and guest. Note that the guest flags are only set if all CPUs have HCRX_EL2. Asymmetric systems where only some CPUs have HCRX_EL2 are not supported and will result in guests running with the host flags set (and a "SANITY CHECK" warning printed for the host). After this change, SMPME is no longer set for guests, which should have no effect as SME is currently disabled for guests. Signed-off-by: Kristina Martsenko <redacted> --- I wasn't sure what to do about asymmetric systems. It seems a bit fragile, maybe someone has a better idea? arch/arm64/include/asm/kvm_arm.h | 1 + arch/arm64/kvm/hyp/include/hyp/switch.h | 6 ++++++ 2 files changed, 7 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index caa31f4ab1cd..cd8dd307aaba 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h@@ -93,6 +93,7 @@ #define HCR_HOST_NVHE_PROTECTED_FLAGS (HCR_HOST_NVHE_FLAGS | HCR_TSC) #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H) +#define HCRX_GUEST_FLAGS 0 #define HCRX_HOST_FLAGS (HCRX_EL2_SMPME) /* TCR_EL2 Registers bits */
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 07d37ff88a3f..a1bf2d879db5 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h@@ -129,6 +129,9 @@ static inline void ___activate_traps(struct kvm_vcpu *vcpu) if (cpus_have_final_cap(ARM64_HAS_RAS_EXTN) && (hcr & HCR_VSE)) write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2); + + if (cpus_have_final_cap(ARM64_HAS_HCX)) + write_sysreg_s(HCRX_GUEST_FLAGS, SYS_HCRX_EL2); } static inline void ___deactivate_traps(struct kvm_vcpu *vcpu)
@@ -143,6 +146,9 @@ static inline void ___deactivate_traps(struct kvm_vcpu *vcpu) vcpu->arch.hcr_el2 &= ~HCR_VSE; vcpu->arch.hcr_el2 |= read_sysreg(hcr_el2) & HCR_VSE; } + + if (cpus_have_final_cap(ARM64_HAS_HCX)) + write_sysreg_s(HCRX_HOST_FLAGS, SYS_HCRX_EL2); } static inline bool __populate_fault_info(struct kvm_vcpu *vcpu)
--
2.25.1
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