[PATCH 1/2] KVM: arm64: Hide TCR2_EL1 from userspace when disabled for guests
From: Mark Brown <broonie@kernel.org>
Date: 2024-08-21 13:14:03
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
When the guest does not support FEAT_TCR2 we should not allow any access
to it in order to ensure that we do not create spurious issues with guest
migration. Add a visibility operation for it.
Fixes: fbff56068232 ("KVM: arm64: Save/restore TCR2_EL1")
Signed-off-by: Mark Brown <broonie@kernel.org>
---
arch/arm64/include/asm/kvm_host.h | 3 +++
arch/arm64/kvm/sys_regs.c | 14 ++++++++++++--
2 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index a33f5996ca9f..47675ef13676 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h@@ -1473,4 +1473,7 @@ void kvm_set_vm_id_reg(struct kvm *kvm, u32 reg, u64 val); (pa + pi + pa3) == 1; \ }) +#define kvm_has_tcr2(k) \ + (kvm_has_feat((k), ID_AA64MMFR3_EL1, TCRX, IMP)) + #endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index c90324060436..aab689ea8992 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c@@ -2255,6 +2255,15 @@ static bool access_zcr_el2(struct kvm_vcpu *vcpu, return true; } +static unsigned int tcr2_visibility(const struct kvm_vcpu *vcpu, + const struct sys_reg_desc *rd) +{ + if (kvm_has_tcr2(vcpu->kvm)) + return 0; + + return REG_HIDDEN; +} + /* * Architected system registers. * Important: Must be sorted ascending by Op0, Op1, CRn, CRm, Op2
@@ -2438,7 +2447,8 @@ static const struct sys_reg_desc sys_reg_descs[] = { { SYS_DESC(SYS_TTBR0_EL1), access_vm_reg, reset_unknown, TTBR0_EL1 }, { SYS_DESC(SYS_TTBR1_EL1), access_vm_reg, reset_unknown, TTBR1_EL1 }, { SYS_DESC(SYS_TCR_EL1), access_vm_reg, reset_val, TCR_EL1, 0 }, - { SYS_DESC(SYS_TCR2_EL1), access_vm_reg, reset_val, TCR2_EL1, 0 }, + { SYS_DESC(SYS_TCR2_EL1), access_vm_reg, reset_val, TCR2_EL1, 0, + .visibility = tcr2_visibility }, PTRAUTH_KEY(APIA), PTRAUTH_KEY(APIB),
@@ -4558,7 +4568,7 @@ void kvm_calculate_traps(struct kvm_vcpu *vcpu) if (kvm_has_feat(kvm, ID_AA64ISAR2_EL1, MOPS, IMP)) vcpu->arch.hcrx_el2 |= (HCRX_EL2_MSCEn | HCRX_EL2_MCE2); - if (kvm_has_feat(kvm, ID_AA64MMFR3_EL1, TCRX, IMP)) + if (kvm_has_tcr2(kvm)) vcpu->arch.hcrx_el2 |= HCRX_EL2_TCR2En; }
--
2.39.2