From: Paolo Bonzini pbonzini@redhat.com
[ Upstream commit 2fdcc1b324189b5fb20655baebd40cd82e2bdf0c ]
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 pbonzini@redhat.com Signed-off-by: Mathias Krause minipli@grsecurity.net Link: https://lore.kernel.org/r/20230322013731.102955-2-minipli@grsecurity.net Signed-off-by: Sean Christopherson seanjc@google.com Signed-off-by: Mathias Krause minipli@grsecurity.net # backport to v5.15.x --- arch/x86/kvm/mmu.h | 11 +++++++++++ arch/x86/kvm/mmu/mmu.c | 12 ++++++------ arch/x86/kvm/mmu/paging_tmpl.h | 2 +- arch/x86/kvm/x86.c | 2 +- 4 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 7bb165c23233..baafc5d8bb9e 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -115,6 +115,17 @@ static inline void kvm_mmu_load_pgd(struct kvm_vcpu *vcpu) vcpu->arch.mmu->shadow_root_level); }
+unsigned long get_guest_cr3(struct kvm_vcpu *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); +} + int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code, bool prefault);
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 4724289c8a7f..7c3b809f24b3 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3472,7 +3472,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) unsigned i; int r;
- 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)) @@ -3899,7 +3899,7 @@ 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->direct_map; - 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); @@ -4203,7 +4203,7 @@ 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) +unsigned long get_guest_cr3(struct kvm_vcpu *vcpu) { return kvm_read_cr3(vcpu); } @@ -4756,7 +4756,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu) context->invlpg = NULL; context->shadow_root_level = kvm_mmu_get_tdp_level(vcpu); context->direct_map = true; - 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; context->root_level = role_regs_to_root_level(®s); @@ -4933,7 +4933,7 @@ static void init_kvm_softmmu(struct kvm_vcpu *vcpu)
kvm_init_shadow_mmu(vcpu, ®s);
- 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; } @@ -4965,7 +4965,7 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu) return;
g_context->mmu_role.as_u64 = new_role.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; g_context->root_level = new_role.base.level; diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index a1811f51eda9..dbb54f65d1df 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -359,7 +359,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, trace_kvm_mmu_pagetable_walk(addr, access); retry_walk: walker->level = mmu->root_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 diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5cb4af42ba64..018f6a394d44 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12155,7 +12155,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work) return;
if (!vcpu->arch.mmu->direct_map && - 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);