From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: [PATCH 23/85] KVM: arm64: Slightly improve debug save/restore functions Date: Wed, 28 Mar 2018 13:51:52 +0100 Message-ID: <20180328125254.31380-24-marc.zyngier@arm.com> References: <20180328125254.31380-1-marc.zyngier@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Christoffer Dall , Christoffer Dall , Shunyong Yang , Julien Thierry , Andre Przywara , Will Deacon , Shih-Wei Li , Catalin Marinas , Dave Martin To: Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org Return-path: In-Reply-To: <20180328125254.31380-1-marc.zyngier@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org From: Christoffer Dall The debug save/restore functions can be improved by using the has_vhe() static key instead of the instruction alternative. Using the static key uses the same paradigm as we're going to use elsewhere, it makes the code more readable, and it generates slightly better code (no stack setups and function calls unless necessary). We also use a static key on the restore path, because it will be marginally faster than loading a value from memory. Finally, we don't have to conditionally clear the debug dirty flag if it's set, we can just clear it. Reviewed-by: Marc Zyngier Reviewed-by: Andrew Jones Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/debug-sr.c | 26 ++++++++++++-------------- 1 file changed, 12 insertions(+), 14 deletions(-) diff --git a/arch/arm64/kvm/hyp/debug-sr.c b/arch/arm64/kvm/hyp/debug-sr.c index d958cd63a547..74f71fb5e36d 100644 --- a/arch/arm64/kvm/hyp/debug-sr.c +++ b/arch/arm64/kvm/hyp/debug-sr.c @@ -66,11 +66,6 @@ default: write_debug(ptr[0], reg, 0); \ } -static void __hyp_text __debug_save_spe_vhe(u64 *pmscr_el1) -{ - /* The vcpu can run. but it can't hide. */ -} - static void __hyp_text __debug_save_spe_nvhe(u64 *pmscr_el1) { u64 reg; @@ -103,11 +98,7 @@ static void __hyp_text __debug_save_spe_nvhe(u64 *pmscr_el1) dsb(nsh); } -static hyp_alternate_select(__debug_save_spe, - __debug_save_spe_nvhe, __debug_save_spe_vhe, - ARM64_HAS_VIRT_HOST_EXTN); - -static void __hyp_text __debug_restore_spe(u64 pmscr_el1) +static void __hyp_text __debug_restore_spe_nvhe(u64 pmscr_el1) { if (!pmscr_el1) return; @@ -168,17 +159,24 @@ void __hyp_text __debug_cond_save_host_state(struct kvm_vcpu *vcpu) { __debug_save_state(vcpu, &vcpu->arch.host_debug_state.regs, kern_hyp_va(vcpu->arch.host_cpu_context)); - __debug_save_spe()(&vcpu->arch.host_debug_state.pmscr_el1); + + /* + * Non-VHE: Disable and flush SPE data generation + * VHE: The vcpu can run, but it can't hide. + */ + if (!has_vhe()) + __debug_save_spe_nvhe(&vcpu->arch.host_debug_state.pmscr_el1); } void __hyp_text __debug_cond_restore_host_state(struct kvm_vcpu *vcpu) { - __debug_restore_spe(vcpu->arch.host_debug_state.pmscr_el1); + if (!has_vhe()) + __debug_restore_spe_nvhe(vcpu->arch.host_debug_state.pmscr_el1); + __debug_restore_state(vcpu, &vcpu->arch.host_debug_state.regs, kern_hyp_va(vcpu->arch.host_cpu_context)); - if (vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY) - vcpu->arch.debug_flags &= ~KVM_ARM64_DEBUG_DIRTY; + vcpu->arch.debug_flags &= ~KVM_ARM64_DEBUG_DIRTY; } u32 __hyp_text __kvm_get_mdcr_el2(void) -- 2.14.2 From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Wed, 28 Mar 2018 13:51:52 +0100 Subject: [PATCH 23/85] KVM: arm64: Slightly improve debug save/restore functions In-Reply-To: <20180328125254.31380-1-marc.zyngier@arm.com> References: <20180328125254.31380-1-marc.zyngier@arm.com> Message-ID: <20180328125254.31380-24-marc.zyngier@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Christoffer Dall The debug save/restore functions can be improved by using the has_vhe() static key instead of the instruction alternative. Using the static key uses the same paradigm as we're going to use elsewhere, it makes the code more readable, and it generates slightly better code (no stack setups and function calls unless necessary). We also use a static key on the restore path, because it will be marginally faster than loading a value from memory. Finally, we don't have to conditionally clear the debug dirty flag if it's set, we can just clear it. Reviewed-by: Marc Zyngier Reviewed-by: Andrew Jones Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/debug-sr.c | 26 ++++++++++++-------------- 1 file changed, 12 insertions(+), 14 deletions(-) diff --git a/arch/arm64/kvm/hyp/debug-sr.c b/arch/arm64/kvm/hyp/debug-sr.c index d958cd63a547..74f71fb5e36d 100644 --- a/arch/arm64/kvm/hyp/debug-sr.c +++ b/arch/arm64/kvm/hyp/debug-sr.c @@ -66,11 +66,6 @@ default: write_debug(ptr[0], reg, 0); \ } -static void __hyp_text __debug_save_spe_vhe(u64 *pmscr_el1) -{ - /* The vcpu can run. but it can't hide. */ -} - static void __hyp_text __debug_save_spe_nvhe(u64 *pmscr_el1) { u64 reg; @@ -103,11 +98,7 @@ static void __hyp_text __debug_save_spe_nvhe(u64 *pmscr_el1) dsb(nsh); } -static hyp_alternate_select(__debug_save_spe, - __debug_save_spe_nvhe, __debug_save_spe_vhe, - ARM64_HAS_VIRT_HOST_EXTN); - -static void __hyp_text __debug_restore_spe(u64 pmscr_el1) +static void __hyp_text __debug_restore_spe_nvhe(u64 pmscr_el1) { if (!pmscr_el1) return; @@ -168,17 +159,24 @@ void __hyp_text __debug_cond_save_host_state(struct kvm_vcpu *vcpu) { __debug_save_state(vcpu, &vcpu->arch.host_debug_state.regs, kern_hyp_va(vcpu->arch.host_cpu_context)); - __debug_save_spe()(&vcpu->arch.host_debug_state.pmscr_el1); + + /* + * Non-VHE: Disable and flush SPE data generation + * VHE: The vcpu can run, but it can't hide. + */ + if (!has_vhe()) + __debug_save_spe_nvhe(&vcpu->arch.host_debug_state.pmscr_el1); } void __hyp_text __debug_cond_restore_host_state(struct kvm_vcpu *vcpu) { - __debug_restore_spe(vcpu->arch.host_debug_state.pmscr_el1); + if (!has_vhe()) + __debug_restore_spe_nvhe(vcpu->arch.host_debug_state.pmscr_el1); + __debug_restore_state(vcpu, &vcpu->arch.host_debug_state.regs, kern_hyp_va(vcpu->arch.host_cpu_context)); - if (vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY) - vcpu->arch.debug_flags &= ~KVM_ARM64_DEBUG_DIRTY; + vcpu->arch.debug_flags &= ~KVM_ARM64_DEBUG_DIRTY; } u32 __hyp_text __kvm_get_mdcr_el2(void) -- 2.14.2