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[2003:f6:af11:1a00:2774:82c0:51ec:a183]) by smtp.gmail.com with ESMTPSA id c23-20020a170906155700b00869f2ca6a87sm10397579ejd.135.2023.02.01.11.44.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Feb 2023 11:44:25 -0800 (PST) From: Mathias Krause To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Sean Christopherson , Paolo Bonzini , Mathias Krause Subject: [PATCH v3 1/6] KVM: x86/mmu: Avoid indirect call for get_cr3 Date: Wed, 1 Feb 2023 20:45:59 +0100 Message-Id: <20230201194604.11135-2-minipli@grsecurity.net> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230201194604.11135-1-minipli@grsecurity.net> References: <20230201194604.11135-1-minipli@grsecurity.net> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Paolo Bonzini Most of the time, calls to get_guest_pgd result in calling kvm_read_cr3 (the exception is only nested TDP). Hardcode the default instead of using the get_cr3 function, avoiding a retpoline if they are enabled. Signed-off-by: Paolo Bonzini Signed-off-by: Mathias Krause --- arch/x86/kvm/mmu/mmu.c | 31 ++++++++++++++++++++----------- arch/x86/kvm/mmu/paging_tmpl.h | 2 +- 2 files changed, 21 insertions(+), 12 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index aeb240b339f5..505768631614 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -241,6 +241,20 @@ static struct kvm_mmu_role_regs vcpu_to_role_regs(struct kvm_vcpu *vcpu) return regs; } +static unsigned long get_guest_cr3(struct kvm_vcpu *vcpu) +{ + return kvm_read_cr3(vcpu); +} + +static inline unsigned long kvm_mmu_get_guest_pgd(struct kvm_vcpu *vcpu, + struct kvm_mmu *mmu) +{ + if (IS_ENABLED(CONFIG_RETPOLINE) && mmu->get_guest_pgd == get_guest_cr3) + return kvm_read_cr3(vcpu); + + return mmu->get_guest_pgd(vcpu); +} + static inline bool kvm_available_flush_tlb_with_range(void) { return kvm_x86_ops.tlb_remote_flush_with_range; @@ -3722,7 +3736,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) int quadrant, i, r; hpa_t root; - root_pgd = mmu->get_guest_pgd(vcpu); + root_pgd = kvm_mmu_get_guest_pgd(vcpu, mmu); root_gfn = root_pgd >> PAGE_SHIFT; if (mmu_check_root(vcpu, root_gfn)) @@ -4172,7 +4186,7 @@ static bool kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, arch.token = alloc_apf_token(vcpu); arch.gfn = gfn; arch.direct_map = vcpu->arch.mmu->root_role.direct; - arch.cr3 = vcpu->arch.mmu->get_guest_pgd(vcpu); + arch.cr3 = kvm_mmu_get_guest_pgd(vcpu, vcpu->arch.mmu); return kvm_setup_async_pf(vcpu, cr2_or_gpa, kvm_vcpu_gfn_to_hva(vcpu, gfn), &arch); @@ -4191,7 +4205,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) return; if (!vcpu->arch.mmu->root_role.direct && - work->arch.cr3 != vcpu->arch.mmu->get_guest_pgd(vcpu)) + work->arch.cr3 != kvm_mmu_get_guest_pgd(vcpu, vcpu->arch.mmu)) return; kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, 0, true); @@ -4592,11 +4606,6 @@ void kvm_mmu_new_pgd(struct kvm_vcpu *vcpu, gpa_t new_pgd) } EXPORT_SYMBOL_GPL(kvm_mmu_new_pgd); -static unsigned long get_cr3(struct kvm_vcpu *vcpu) -{ - return kvm_read_cr3(vcpu); -} - static bool sync_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn, unsigned int access) { @@ -5147,7 +5156,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu, context->page_fault = kvm_tdp_page_fault; context->sync_page = nonpaging_sync_page; context->invlpg = NULL; - context->get_guest_pgd = get_cr3; + context->get_guest_pgd = get_guest_cr3; context->get_pdptr = kvm_pdptr_read; context->inject_page_fault = kvm_inject_page_fault; @@ -5297,7 +5306,7 @@ static void init_kvm_softmmu(struct kvm_vcpu *vcpu, kvm_init_shadow_mmu(vcpu, cpu_role); - context->get_guest_pgd = get_cr3; + context->get_guest_pgd = get_guest_cr3; context->get_pdptr = kvm_pdptr_read; context->inject_page_fault = kvm_inject_page_fault; } @@ -5311,7 +5320,7 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu, return; g_context->cpu_role.as_u64 = new_mode.as_u64; - g_context->get_guest_pgd = get_cr3; + g_context->get_guest_pgd = get_guest_cr3; g_context->get_pdptr = kvm_pdptr_read; g_context->inject_page_fault = kvm_inject_page_fault; diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index e5662dbd519c..78448fb84bd6 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -324,7 +324,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, trace_kvm_mmu_pagetable_walk(addr, access); retry_walk: walker->level = mmu->cpu_role.base.level; - pte = mmu->get_guest_pgd(vcpu); + pte = kvm_mmu_get_guest_pgd(vcpu, mmu); have_ad = PT_HAVE_ACCESSED_DIRTY(mmu); #if PTTYPE == 64 -- 2.39.1