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| author | Marc Zyngier <marc.zyngier@arm.com> | 2018-08-23 11:51:43 +0100 |
|---|---|---|
| committer | Christoffer Dall <christoffer.dall@arm.com> | 2018-09-07 15:05:50 +0200 |
| commit | 7d14919c0d475a795c0127631ac8ecb2b0f31831 (patch) | |
| tree | 84f8fac05bacd87e4e448acec0562305c927fbc0 /arch/arm64 | |
| parent | 694556d54f354d3fe43bb2e61fd6103cca2638a4 (diff) | |
| download | linux-7d14919c0d475a795c0127631ac8ecb2b0f31831.tar.bz2 | |
arm64: KVM: Only force FPEXC32_EL2.EN if trapping FPSIMD
If trapping FPSIMD in the context of an AArch32 guest, it is critical
to set FPEXC32_EL2.EN to 1 so that the trapping is taken to EL2 and
not EL1.
Conversely, it is just as critical *not* to set FPEXC32_EL2.EN to 1
if we're not going to trap FPSIMD, as we then corrupt the existing
VFP state.
Moving the call to __activate_traps_fpsimd32 to the point where we
know for sure that we are going to trap ensures that we don't set that
bit spuriously.
Fixes: e6b673b741ea ("KVM: arm64: Optimise FPSIMD handling to reduce guest/host thrashing")
Cc: stable@vger.kernel.org # v4.18
Cc: Dave Martin <dave.martin@arm.com>
Reported-by: Alexander Graf <agraf@suse.de>
Tested-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/kvm/hyp/switch.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index d496ef579859..ca46153d7915 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -98,8 +98,10 @@ static void activate_traps_vhe(struct kvm_vcpu *vcpu) val = read_sysreg(cpacr_el1); val |= CPACR_EL1_TTA; val &= ~CPACR_EL1_ZEN; - if (!update_fp_enabled(vcpu)) + if (!update_fp_enabled(vcpu)) { val &= ~CPACR_EL1_FPEN; + __activate_traps_fpsimd32(vcpu); + } write_sysreg(val, cpacr_el1); @@ -114,8 +116,10 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu) val = CPTR_EL2_DEFAULT; val |= CPTR_EL2_TTA | CPTR_EL2_TZ; - if (!update_fp_enabled(vcpu)) + if (!update_fp_enabled(vcpu)) { val |= CPTR_EL2_TFP; + __activate_traps_fpsimd32(vcpu); + } write_sysreg(val, cptr_el2); } @@ -129,7 +133,6 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && (hcr & HCR_VSE)) write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2); - __activate_traps_fpsimd32(vcpu); if (has_vhe()) activate_traps_vhe(vcpu); else |