[PATCH OLK-6.6 0/2] *** CVE-2026-64513 ***
*** BLURB HERE *** Carlos López (1): KVM: x86: Unconditionally recompute CR8 intercept on PPR update Sean Christopherson (1): KVM: x86: Move update_cr8_intercept() to lapic.c arch/x86/kvm/lapic.c | 28 ++++++++++++++++++++++++++++ arch/x86/kvm/lapic.h | 1 + arch/x86/kvm/x86.c | 35 ++--------------------------------- 3 files changed, 31 insertions(+), 33 deletions(-) -- 2.34.1
From: Sean Christopherson <seanjc@google.com> mainline inclusion from mainline-v6.11-rc1 commit c7722e5e1daeeabbd9f969554d52bb7158120b27 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/16812 CVE: CVE-2026-64513 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Move update_cr8_intercept() to lapic.c so that it's globally visible in anticipation of extracting most of the register-specific code out of x86.c and into a new compilation unit. Opportunistically prefix the helper kvm_lapic_ to make its role/scope more obvious. No functional change intended. Reviewed-by: Kai Huang <kai.huang@intel.com> Reviewed-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260529222223.870923-14-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com> Conflicts: arch/x86/kvm/lapic.c arch/x86/kvm/lapic.h arch/x86/kvm/x86.c [896046474f8d ("KVM: x86: Introduce kvm_x86_call() to simplify static calls of kvm_x86_ops") not merged] Signed-off-by: Zhang Kunbo <zhangkunbo@huawei.com> --- arch/x86/kvm/lapic.c | 26 ++++++++++++++++++++++++++ arch/x86/kvm/lapic.h | 1 + arch/x86/kvm/x86.c | 34 +++------------------------------- 3 files changed, 30 insertions(+), 31 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 6ab159b0e326..6afeba6298e5 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -2594,6 +2594,32 @@ u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu) return (tpr & 0xf0) >> 4; } +void kvm_lapic_update_cr8_intercept(struct kvm_vcpu *vcpu) +{ + int max_irr, tpr; + + if (!kvm_x86_ops.update_cr8_intercept) + return; + + if (!lapic_in_kernel(vcpu)) + return; + + if (vcpu->arch.apic->apicv_active) + return; + + if (!vcpu->arch.apic->vapic_addr) + max_irr = kvm_lapic_find_highest_irr(vcpu); + else + max_irr = -1; + + if (max_irr != -1) + max_irr >>= 4; + + tpr = kvm_lapic_get_cr8(vcpu); + + static_call(kvm_x86_update_cr8_intercept)(vcpu, tpr, max_irr); +} + void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value) { u64 old_value = vcpu->arch.apic_base; diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 0dd069b8d6d1..bab045776655 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -95,6 +95,7 @@ int kvm_apic_accept_events(struct kvm_vcpu *vcpu); void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event); u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu); void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8); +void kvm_lapic_update_cr8_intercept(struct kvm_vcpu *vcpu); void kvm_lapic_set_eoi(struct kvm_vcpu *vcpu); void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value); u64 kvm_lapic_get_base(struct kvm_vcpu *vcpu); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 191c350345b8..8c265e5a53c9 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -124,7 +124,6 @@ static u64 __read_mostly cr4_reserved_bits = CR4_RESERVED_BITS; #define KVM_X2APIC_API_VALID_FLAGS (KVM_X2APIC_API_USE_32BIT_IDS | \ KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK) -static void update_cr8_intercept(struct kvm_vcpu *vcpu); static void process_nmi(struct kvm_vcpu *vcpu); static void __kvm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags); static void store_regs(struct kvm_vcpu *vcpu); @@ -5123,7 +5122,7 @@ static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu, r = kvm_apic_set_state(vcpu, s); if (r) return r; - update_cr8_intercept(vcpu); + kvm_lapic_update_cr8_intercept(vcpu); return 0; } @@ -10315,33 +10314,6 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu) kvm_run->flags |= KVM_RUN_X86_SMM; } -static void update_cr8_intercept(struct kvm_vcpu *vcpu) -{ - int max_irr, tpr; - - if (!kvm_x86_ops.update_cr8_intercept) - return; - - if (!lapic_in_kernel(vcpu)) - return; - - if (vcpu->arch.apic->apicv_active) - return; - - if (!vcpu->arch.apic->vapic_addr) - max_irr = kvm_lapic_find_highest_irr(vcpu); - else - max_irr = -1; - - if (max_irr != -1) - max_irr >>= 4; - - tpr = kvm_lapic_get_cr8(vcpu); - - static_call(kvm_x86_update_cr8_intercept)(vcpu, tpr, max_irr); -} - - int kvm_check_nested_events(struct kvm_vcpu *vcpu) { if (kvm_test_request(KVM_REQ_TRIPLE_FAULT, vcpu)) { @@ -11046,7 +11018,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) static_call(kvm_x86_enable_irq_window)(vcpu); if (kvm_lapic_enabled(vcpu)) { - update_cr8_intercept(vcpu); + kvm_lapic_update_cr8_intercept(vcpu); kvm_lapic_sync_to_vapic(vcpu); } } @@ -11987,7 +11959,7 @@ static int __set_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs, kvm_set_segment(vcpu, &sregs->tr, VCPU_SREG_TR); kvm_set_segment(vcpu, &sregs->ldt, VCPU_SREG_LDTR); - update_cr8_intercept(vcpu); + kvm_lapic_update_cr8_intercept(vcpu); /* Older userspace won't unhalt the vcpu on reset. */ if (kvm_vcpu_is_bsp(vcpu) && kvm_rip_read(vcpu) == 0xfff0 && -- 2.34.1
From: Carlos López <clopez@suse.de> stable inclusion from stable-v6.18.39 commit ff9c4c6428883182960cfe5c78928f0896d80ebc category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/16812 CVE: CVE-2026-64513 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit bb365a506b1e6fb050c0fceaad354fe395385ef0 ] The TPR_THRESHOLD field in the VMCS is used by VMX to induce VM exits when the guest's virtual TPR falls under the specified threshold, allowing KVM to inject previously masked interrupts. KVM handles these VM exits in handle_tpr_below_threshold(). Commit eb90f3417a0c ("KVM: vmx: speed up TPR below threshold vmexits") optimized this function by calling apic_update_ppr() instead of raising KVM_REQ_EVENT. apic_update_ppr() then raises KVM_REQ_EVENT if there is a pending, deliverable interrupt. However, if there are no new interrupts pending, apic_update_ppr() does not issue the request. Thus, kvm_lapic_update_cr8_intercept() and vmx_update_cr8_intercept() are not called before VM entry, which results in a high, stale TPR_THRESHOLD. This is problematic due to the following sentence in 28.2.1.1 "VM-Execution Control Fields" in the SDM: The following check is performed if the “use TPR shadow” VM-execution control is 1 and the “virtualize APIC accesses” and “virtual-interrupt delivery” VM-execution controls are both 0: the value of bits 3:0 of the TPR threshold VM-execution control field should not be greater than the value of bits 7:4 of VTPR. This error condition is typically not observed when KVM runs on a bare metal system because modern processors support APICv, which enables virtual-interrupt delivery, and which KVM uses when possible. This causes the processor to no longer generate TPR-below-threshold exits and to no longer check TPR_THRESHOLD on entry. However, when running on older platforms, or under nested virtualization on a hypervisor that does not support virtual-interrupt delivery and enforces this check (like Hyper-V) this can cause a VM entry failure with hardware error 0x7, as seen in [1]. Call kvm_lapic_update_cr8_intercept() if apic_update_ppr() does not find a deliverable interrupt (and thus does not raise KVM_REQ_EVENT). Remove calls to kvm_lapic_update_cr8_intercept() on paths that end up in apic_update_ppr(), as they now become redundant. This ensures that any path that updates the guest's PPR also figures out if KVM needs to wait for a TPR change (using TPR_THRESHOLD on VMX or CR8 intercepts on SVM). Link: https://github.com/coconut-svsm/svsm/issues/1081 [1] Tested-by: Stefano Garzarella <sgarzare@redhat.com> Cc: stable@vger.kernel.org Fixes: eb90f3417a0c ("KVM: vmx: speed up TPR below threshold vmexits") Signed-off-by: Carlos López <clopez@suse.de> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-ID: <20260618174347.1981064-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: arch/x86/kvm/lapic.c arch/x86/kvm/x86.c [context conflicts] Signed-off-by: Zhang Kunbo <zhangkunbo@huawei.com> --- arch/x86/kvm/lapic.c | 2 ++ arch/x86/kvm/x86.c | 5 +---- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 6afeba6298e5..3bf22ff6aacb 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -981,6 +981,8 @@ static void apic_update_ppr(struct kvm_lapic *apic) if (__apic_update_ppr(apic, &ppr) && apic_has_interrupt_for_ppr(apic, ppr) != -1) kvm_make_request(KVM_REQ_EVENT, apic->vcpu); + else + kvm_lapic_update_cr8_intercept(apic->vcpu); } void kvm_apic_update_ppr(struct kvm_vcpu *vcpu) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8c265e5a53c9..541e3f696814 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5122,7 +5122,6 @@ static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu, r = kvm_apic_set_state(vcpu, s); if (r) return r; - kvm_lapic_update_cr8_intercept(vcpu); return 0; } @@ -11925,8 +11924,6 @@ static int __set_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs, static_call_cond(kvm_x86_post_set_cr3)(vcpu, sregs->cr3); skip_dt_cr2_cr3: - kvm_set_cr8(vcpu, sregs->cr8); - *mmu_reset_needed |= vcpu->arch.efer != sregs->efer; static_call(kvm_x86_set_efer)(vcpu, sregs->efer); @@ -11959,7 +11956,7 @@ static int __set_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs, kvm_set_segment(vcpu, &sregs->tr, VCPU_SREG_TR); kvm_set_segment(vcpu, &sregs->ldt, VCPU_SREG_LDTR); - kvm_lapic_update_cr8_intercept(vcpu); + kvm_set_cr8(vcpu, sregs->cr8); /* Older userspace won't unhalt the vcpu on reset. */ if (kvm_vcpu_is_bsp(vcpu) && kvm_rip_read(vcpu) == 0xfff0 && -- 2.34.1
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