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[80.210.64.78]) by smtp.gmail.com with ESMTPSA id a16sm2868270edd.19.2017.12.07.09.07.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 07 Dec 2017 09:07:24 -0800 (PST) From: Christoffer Dall To: kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Cc: kvm@vger.kernel.org, Marc Zyngier , Shih-Wei Li , Andrew Jones , Christoffer Dall Subject: [PATCH v2 28/36] KVM: arm64: Configure FPSIMD traps on vcpu load/put for VHE Date: Thu, 7 Dec 2017 18:06:22 +0100 Message-Id: <20171207170630.592-29-christoffer.dall@linaro.org> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171207170630.592-1-christoffer.dall@linaro.org> References: <20171207170630.592-1-christoffer.dall@linaro.org> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP There is no need to enable/disable traps to FP registers on every switch to/from the VM, because the host kernel does not use this resource without calling vcpu_put. We can therefore move things around enough that we still always write FPEXC32_EL2 before programming CPTR_EL2 but only program these during vcpu load/put. Signed-off-by: Christoffer Dall --- arch/arm64/include/asm/kvm_hyp.h | 3 +++ arch/arm64/kvm/hyp/switch.c | 34 ++++++++++++++++++++++++---------- arch/arm64/kvm/hyp/sysreg-sr.c | 4 ++++ 3 files changed, 31 insertions(+), 10 deletions(-) diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h index 3f54c55f77a1..28d5f3cb4001 100644 --- a/arch/arm64/include/asm/kvm_hyp.h +++ b/arch/arm64/include/asm/kvm_hyp.h @@ -148,6 +148,9 @@ void __fpsimd_save_state(struct user_fpsimd_state *fp_regs); void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs); bool __fpsimd_enabled(void); +void activate_traps_vhe_load(struct kvm_vcpu *vcpu); +void deactivate_traps_vhe_put(void); + u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt); void __noreturn __hyp_do_panic(unsigned long, ...); diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index c01bcfc3fb52..44aae69a7fec 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -24,22 +24,25 @@ #include #include -static void __hyp_text __activate_traps_common(struct kvm_vcpu *vcpu) +static void __hyp_text __activate_traps_fpsimd32(struct kvm_vcpu *vcpu) { /* - * We are about to set CPTR_EL2.TFP to trap all floating point - * register accesses to EL2, however, the ARM ARM clearly states that - * traps are only taken to EL2 if the operation would not otherwise - * trap to EL1. Therefore, always make sure that for 32-bit guests, - * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit. - * If FP/ASIMD is not implemented, FPEXC is UNDEFINED and any access to - * it will cause an exception. + * We are about to trap all floating point register accesses to EL2, + * however, traps are only taken to EL2 if the operation would not + * otherwise trap to EL1. Therefore, always make sure that for 32-bit + * guests, we set FPEXC.EN to prevent traps to EL1, when setting the + * TFP bit. If FP/ASIMD is not implemented, FPEXC is UNDEFINED and + * any access to it will cause an exception. */ if (vcpu_el1_is_32bit(vcpu) && system_supports_fpsimd() && !vcpu->arch.guest_vfp_loaded) { write_sysreg(1 << 30, fpexc32_el2); isb(); } +} + +static void __hyp_text __activate_traps_common(struct kvm_vcpu *vcpu) +{ write_sysreg(vcpu->arch.hcr_el2, hcr_el2); /* Trap on AArch32 cp15 c15 (impdef sysregs) accesses (EL1 or EL0) */ @@ -61,10 +64,12 @@ static void __hyp_text __deactivate_traps_common(void) write_sysreg(0, pmuserenr_el0); } -static void __hyp_text __activate_traps_vhe(struct kvm_vcpu *vcpu) +void activate_traps_vhe_load(struct kvm_vcpu *vcpu) { u64 val; + __activate_traps_fpsimd32(vcpu); + val = read_sysreg(cpacr_el1); val |= CPACR_EL1_TTA; val &= ~CPACR_EL1_ZEN; @@ -73,7 +78,15 @@ static void __hyp_text __activate_traps_vhe(struct kvm_vcpu *vcpu) else val &= ~CPACR_EL1_FPEN; write_sysreg(val, cpacr_el1); +} +void deactivate_traps_vhe_put(void) +{ + write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1); +} + +static void __hyp_text __activate_traps_vhe(struct kvm_vcpu *vcpu) +{ write_sysreg(__kvm_hyp_vector, vbar_el1); } @@ -81,6 +94,8 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu) { u64 val; + __activate_traps_fpsimd32(vcpu); + val = CPTR_EL2_DEFAULT; val |= CPTR_EL2_TTA | CPTR_EL2_TZ; if (vcpu->arch.guest_vfp_loaded) @@ -111,7 +126,6 @@ static void __hyp_text __deactivate_traps_vhe(void) write_sysreg(mdcr_el2, mdcr_el2); write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); - write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1); write_sysreg(vectors, vbar_el1); } diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c index 65abf1aeba59..b647fea93fdc 100644 --- a/arch/arm64/kvm/hyp/sysreg-sr.c +++ b/arch/arm64/kvm/hyp/sysreg-sr.c @@ -254,6 +254,8 @@ void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) __sysreg_restore_el1_state(guest_ctxt); vcpu->arch.sysregs_loaded_on_cpu = true; + + activate_traps_vhe_load(vcpu); } /** @@ -286,6 +288,8 @@ void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) if (!has_vhe()) return; + deactivate_traps_vhe_put(); + __sysreg_save_el1_state(guest_ctxt); __sysreg_save_user_state(guest_ctxt); __sysreg32_save_state(vcpu);