[PATCH 3/5] KVM: arm64: Make TCR2_EL1 save/restore dependent on the VM features

Marc Zyngier
2024-06-25T13:00:49Z

As for other registers, save/restore of TCR2_EL1 should be gated
on the feature being actually present.

In the case of a nVHE hypervisor, it is perfectly fine to leave
the host value in the register, as HCRX_EL2.TCREn==0 imposes that
TCR2_EL1 is treated as 0.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
index 4be6a7fa00708..ea2aeeff61db7 100644
--- a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
+++ b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
@@ -55,6 +55,17 @@ static inline bool ctxt_has_s1pie(struct kvm_cpu_context *ctxt)
return kvm_has_feat(kern_hyp_va(vcpu->kvm), ID_AA64MMFR3_EL1, S1PIE, IMP);
}

+static inline bool ctxt_has_tcrx(struct kvm_cpu_context *ctxt)
+{
+ struct kvm_vcpu *vcpu;
+
+ if (!cpus_have_final_cap(ARM64_HAS_TCR2))
+ return false;
+
+ vcpu = ctxt_to_vcpu(ctxt);
+ return kvm_has_feat(kern_hyp_va(vcpu->kvm), ID_AA64MMFR3_EL1, TCRX, IMP);
+}
+
static inline void __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
{
ctxt_sys_reg(ctxt, SCTLR_EL1) = read_sysreg_el1(SYS_SCTLR);
@@ -62,7 +73,7 @@ static inline void __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
ctxt_sys_reg(ctxt, TTBR0_EL1) = read_sysreg_el1(SYS_TTBR0);
ctxt_sys_reg(ctxt, TTBR1_EL1) = read_sysreg_el1(SYS_TTBR1);
ctxt_sys_reg(ctxt, TCR_EL1) = read_sysreg_el1(SYS_TCR);
- if (cpus_have_final_cap(ARM64_HAS_TCR2))
+ if (ctxt_has_tcrx(ctxt))
ctxt_sys_reg(ctxt, TCR2_EL1) = read_sysreg_el1(SYS_TCR2);
ctxt_sys_reg(ctxt, ESR_EL1) = read_sysreg_el1(SYS_ESR);
ctxt_sys_reg(ctxt, AFSR0_EL1) = read_sysreg_el1(SYS_AFSR0);
@@ -138,7 +149,7 @@ static inline void __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
write_sysreg_el1(ctxt_sys_reg(ctxt, CPACR_EL1), SYS_CPACR);
write_sysreg_el1(ctxt_sys_reg(ctxt, TTBR0_EL1), SYS_TTBR0);
write_sysreg_el1(ctxt_sys_reg(ctxt, TTBR1_EL1), SYS_TTBR1);
- if (cpus_have_final_cap(ARM64_HAS_TCR2))
+ if (ctxt_has_tcrx(ctxt))
write_sysreg_el1(ctxt_sys_reg(ctxt, TCR2_EL1), SYS_TCR2);
write_sysreg_el1(ctxt_sys_reg(ctxt, ESR_EL1), SYS_ESR);
write_sysreg_el1(ctxt_sys_reg(ctxt, AFSR0_EL1), SYS_AFSR0);
--
2.39.2