[PATCH v2 25/26] KVM: arm64: Move HCRX_EL2 switch to load/put on VHE systems
Marc Zyngier
maz at kernel.org
Fri Jul 28 01:29:51 PDT 2023
Although the nVHE behaviour requires HCRX_EL2 to be switched
on each switch between host and guest, there is nothing in
this register that would affect a VHE host.
It is thus possible to save/restore this register on load/put
on VHE systems, avoiding unnecessary sysreg access on the hot
path. Additionally, it avoids unnecessary traps when running
with NV.
To achieve this, simply move the read/writes to the *_common()
helpers, which are called on load/put on VHE, and more eagerly
on nVHE.
Signed-off-by: Marc Zyngier <maz at kernel.org>
---
arch/arm64/kvm/hyp/include/hyp/switch.h | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index ad9c730b7d1a..5bcffd1906ce 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -197,6 +197,9 @@ static inline void __activate_traps_common(struct kvm_vcpu *vcpu)
vcpu->arch.mdcr_el2_host = read_sysreg(mdcr_el2);
write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
+ if (cpus_have_final_cap(ARM64_HAS_HCX))
+ write_sysreg_s(HCRX_GUEST_FLAGS, SYS_HCRX_EL2);
+
__activate_traps_hfgxtr(vcpu);
}
@@ -213,6 +216,9 @@ static inline void __deactivate_traps_common(struct kvm_vcpu *vcpu)
vcpu_clear_flag(vcpu, PMUSERENR_ON_CPU);
}
+ if (cpus_have_final_cap(ARM64_HAS_HCX))
+ write_sysreg_s(HCRX_HOST_FLAGS, SYS_HCRX_EL2);
+
__deactivate_traps_hfgxtr(vcpu);
}
@@ -227,9 +233,6 @@ 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)
@@ -244,9 +247,6 @@ 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)
--
2.34.1
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