June 2022 - Linux-stable-mirror

[PATCH stable 5.15.y 0/5] missing random.c-related stable patches

by Jason A. Donenfeld

Hi Greg, I forgot two things when doing the 5.15 backport. The first is a patch from Justin fixing a bug in some of the lib/crypto Kconfig changes, which Pablo (CC'd) pointed out was missed. The second is that the backport of 5acd35487dc9 ("random: replace custom notifier chain with standard one") isn't quite right without Nicolai's patches there too, since the drbg module is removable. I'll continue to monitor all the channels I possibly can for chatter about problems, but so far this is all I've run into. Jason Cc: Pablo Greco <pgreco(a)centosproject.org> Justin M. Forbes (1): lib/crypto: add prompts back to crypto libraries Nicolai Stange (4): crypto: drbg - prepare for more fine-grained tracking of seeding state crypto: drbg - track whether DRBG was seeded with !rng_is_initialized() crypto: drbg - move dynamic ->reseed_threshold adjustments to __drbg_seed() crypto: drbg - make reseeding from get_random_bytes() synchronous crypto/Kconfig | 2 - crypto/drbg.c | 110 +++++++++++++++++------------------------- drivers/char/random.c | 2 - include/crypto/drbg.h | 10 ++-- lib/Kconfig | 2 + lib/crypto/Kconfig | 17 +++++-- 6 files changed, 65 insertions(+), 78 deletions(-) -- 2.35.1

2 years, 6 months

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FAILED: patch "[PATCH] KVM: x86: avoid loading a vCPU after .vm_destroy was called" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 6fcee03df6a1a3101a77344be37bb85c6142d56c Mon Sep 17 00:00:00 2001 From: Maxim Levitsky <mlevitsk(a)redhat.com> Date: Tue, 22 Mar 2022 19:24:42 +0200 Subject: [PATCH] KVM: x86: avoid loading a vCPU after .vm_destroy was called This can cause various unexpected issues, since VM is partially destroyed at that point. For example when AVIC is enabled, this causes avic_vcpu_load to access physical id page entry which is already freed by .vm_destroy. Fixes: 8221c1370056 ("svm: Manage vcpu load/unload when enable AVIC") Cc: stable(a)vger.kernel.org Signed-off-by: Maxim Levitsky <mlevitsk(a)redhat.com> Message-Id: <20220322172449.235575-2-mlevitsk(a)redhat.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1abce22b14d7..ba4faeb32437 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11816,20 +11816,15 @@ static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu) vcpu_put(vcpu); } -static void kvm_free_vcpus(struct kvm *kvm) +static void kvm_unload_vcpu_mmus(struct kvm *kvm) { unsigned long i; struct kvm_vcpu *vcpu; - /* - * Unpin any mmu pages first. - */ kvm_for_each_vcpu(i, vcpu, kvm) { kvm_clear_async_pf_completion_queue(vcpu); kvm_unload_vcpu_mmu(vcpu); } - - kvm_destroy_vcpus(kvm); } void kvm_arch_sync_events(struct kvm *kvm) @@ -11935,11 +11930,12 @@ void kvm_arch_destroy_vm(struct kvm *kvm) __x86_set_memory_region(kvm, TSS_PRIVATE_MEMSLOT, 0, 0); mutex_unlock(&kvm->slots_lock); } + kvm_unload_vcpu_mmus(kvm); static_call_cond(kvm_x86_vm_destroy)(kvm); kvm_free_msr_filter(srcu_dereference_check(kvm->arch.msr_filter, &kvm->srcu, 1)); kvm_pic_destroy(kvm); kvm_ioapic_destroy(kvm); - kvm_free_vcpus(kvm); + kvm_destroy_vcpus(kvm); kvfree(rcu_dereference_check(kvm->arch.apic_map, 1)); kfree(srcu_dereference_check(kvm->arch.pmu_event_filter, &kvm->srcu, 1)); kvm_mmu_uninit_vm(kvm);

2 years, 6 months

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FAILED: patch "[PATCH] KVM: x86: avoid loading a vCPU after .vm_destroy was called" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 6fcee03df6a1a3101a77344be37bb85c6142d56c Mon Sep 17 00:00:00 2001 From: Maxim Levitsky <mlevitsk(a)redhat.com> Date: Tue, 22 Mar 2022 19:24:42 +0200 Subject: [PATCH] KVM: x86: avoid loading a vCPU after .vm_destroy was called This can cause various unexpected issues, since VM is partially destroyed at that point. For example when AVIC is enabled, this causes avic_vcpu_load to access physical id page entry which is already freed by .vm_destroy. Fixes: 8221c1370056 ("svm: Manage vcpu load/unload when enable AVIC") Cc: stable(a)vger.kernel.org Signed-off-by: Maxim Levitsky <mlevitsk(a)redhat.com> Message-Id: <20220322172449.235575-2-mlevitsk(a)redhat.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1abce22b14d7..ba4faeb32437 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11816,20 +11816,15 @@ static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu) vcpu_put(vcpu); } -static void kvm_free_vcpus(struct kvm *kvm) +static void kvm_unload_vcpu_mmus(struct kvm *kvm) { unsigned long i; struct kvm_vcpu *vcpu; - /* - * Unpin any mmu pages first. - */ kvm_for_each_vcpu(i, vcpu, kvm) { kvm_clear_async_pf_completion_queue(vcpu); kvm_unload_vcpu_mmu(vcpu); } - - kvm_destroy_vcpus(kvm); } void kvm_arch_sync_events(struct kvm *kvm) @@ -11935,11 +11930,12 @@ void kvm_arch_destroy_vm(struct kvm *kvm) __x86_set_memory_region(kvm, TSS_PRIVATE_MEMSLOT, 0, 0); mutex_unlock(&kvm->slots_lock); } + kvm_unload_vcpu_mmus(kvm); static_call_cond(kvm_x86_vm_destroy)(kvm); kvm_free_msr_filter(srcu_dereference_check(kvm->arch.msr_filter, &kvm->srcu, 1)); kvm_pic_destroy(kvm); kvm_ioapic_destroy(kvm); - kvm_free_vcpus(kvm); + kvm_destroy_vcpus(kvm); kvfree(rcu_dereference_check(kvm->arch.apic_map, 1)); kfree(srcu_dereference_check(kvm->arch.pmu_event_filter, &kvm->srcu, 1)); kvm_mmu_uninit_vm(kvm);

2 years, 6 months

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FAILED: patch "[PATCH] KVM: x86: avoid loading a vCPU after .vm_destroy was called" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 6fcee03df6a1a3101a77344be37bb85c6142d56c Mon Sep 17 00:00:00 2001 From: Maxim Levitsky <mlevitsk(a)redhat.com> Date: Tue, 22 Mar 2022 19:24:42 +0200 Subject: [PATCH] KVM: x86: avoid loading a vCPU after .vm_destroy was called This can cause various unexpected issues, since VM is partially destroyed at that point. For example when AVIC is enabled, this causes avic_vcpu_load to access physical id page entry which is already freed by .vm_destroy. Fixes: 8221c1370056 ("svm: Manage vcpu load/unload when enable AVIC") Cc: stable(a)vger.kernel.org Signed-off-by: Maxim Levitsky <mlevitsk(a)redhat.com> Message-Id: <20220322172449.235575-2-mlevitsk(a)redhat.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1abce22b14d7..ba4faeb32437 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11816,20 +11816,15 @@ static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu) vcpu_put(vcpu); } -static void kvm_free_vcpus(struct kvm *kvm) +static void kvm_unload_vcpu_mmus(struct kvm *kvm) { unsigned long i; struct kvm_vcpu *vcpu; - /* - * Unpin any mmu pages first. - */ kvm_for_each_vcpu(i, vcpu, kvm) { kvm_clear_async_pf_completion_queue(vcpu); kvm_unload_vcpu_mmu(vcpu); } - - kvm_destroy_vcpus(kvm); } void kvm_arch_sync_events(struct kvm *kvm) @@ -11935,11 +11930,12 @@ void kvm_arch_destroy_vm(struct kvm *kvm) __x86_set_memory_region(kvm, TSS_PRIVATE_MEMSLOT, 0, 0); mutex_unlock(&kvm->slots_lock); } + kvm_unload_vcpu_mmus(kvm); static_call_cond(kvm_x86_vm_destroy)(kvm); kvm_free_msr_filter(srcu_dereference_check(kvm->arch.msr_filter, &kvm->srcu, 1)); kvm_pic_destroy(kvm); kvm_ioapic_destroy(kvm); - kvm_free_vcpus(kvm); + kvm_destroy_vcpus(kvm); kvfree(rcu_dereference_check(kvm->arch.apic_map, 1)); kfree(srcu_dereference_check(kvm->arch.pmu_event_filter, &kvm->srcu, 1)); kvm_mmu_uninit_vm(kvm);

2 years, 6 months

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FAILED: patch "[PATCH] KVM: x86: avoid loading a vCPU after .vm_destroy was called" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 6fcee03df6a1a3101a77344be37bb85c6142d56c Mon Sep 17 00:00:00 2001 From: Maxim Levitsky <mlevitsk(a)redhat.com> Date: Tue, 22 Mar 2022 19:24:42 +0200 Subject: [PATCH] KVM: x86: avoid loading a vCPU after .vm_destroy was called This can cause various unexpected issues, since VM is partially destroyed at that point. For example when AVIC is enabled, this causes avic_vcpu_load to access physical id page entry which is already freed by .vm_destroy. Fixes: 8221c1370056 ("svm: Manage vcpu load/unload when enable AVIC") Cc: stable(a)vger.kernel.org Signed-off-by: Maxim Levitsky <mlevitsk(a)redhat.com> Message-Id: <20220322172449.235575-2-mlevitsk(a)redhat.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1abce22b14d7..ba4faeb32437 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11816,20 +11816,15 @@ static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu) vcpu_put(vcpu); } -static void kvm_free_vcpus(struct kvm *kvm) +static void kvm_unload_vcpu_mmus(struct kvm *kvm) { unsigned long i; struct kvm_vcpu *vcpu; - /* - * Unpin any mmu pages first. - */ kvm_for_each_vcpu(i, vcpu, kvm) { kvm_clear_async_pf_completion_queue(vcpu); kvm_unload_vcpu_mmu(vcpu); } - - kvm_destroy_vcpus(kvm); } void kvm_arch_sync_events(struct kvm *kvm) @@ -11935,11 +11930,12 @@ void kvm_arch_destroy_vm(struct kvm *kvm) __x86_set_memory_region(kvm, TSS_PRIVATE_MEMSLOT, 0, 0); mutex_unlock(&kvm->slots_lock); } + kvm_unload_vcpu_mmus(kvm); static_call_cond(kvm_x86_vm_destroy)(kvm); kvm_free_msr_filter(srcu_dereference_check(kvm->arch.msr_filter, &kvm->srcu, 1)); kvm_pic_destroy(kvm); kvm_ioapic_destroy(kvm); - kvm_free_vcpus(kvm); + kvm_destroy_vcpus(kvm); kvfree(rcu_dereference_check(kvm->arch.apic_map, 1)); kfree(srcu_dereference_check(kvm->arch.pmu_event_filter, &kvm->srcu, 1)); kvm_mmu_uninit_vm(kvm);

2 years, 6 months

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FAILED: patch "[PATCH] KVM: x86: avoid loading a vCPU after .vm_destroy was called" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 6fcee03df6a1a3101a77344be37bb85c6142d56c Mon Sep 17 00:00:00 2001 From: Maxim Levitsky <mlevitsk(a)redhat.com> Date: Tue, 22 Mar 2022 19:24:42 +0200 Subject: [PATCH] KVM: x86: avoid loading a vCPU after .vm_destroy was called This can cause various unexpected issues, since VM is partially destroyed at that point. For example when AVIC is enabled, this causes avic_vcpu_load to access physical id page entry which is already freed by .vm_destroy. Fixes: 8221c1370056 ("svm: Manage vcpu load/unload when enable AVIC") Cc: stable(a)vger.kernel.org Signed-off-by: Maxim Levitsky <mlevitsk(a)redhat.com> Message-Id: <20220322172449.235575-2-mlevitsk(a)redhat.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1abce22b14d7..ba4faeb32437 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11816,20 +11816,15 @@ static void kvm_unload_vcpu_mmu(struct kvm_vcpu *vcpu) vcpu_put(vcpu); } -static void kvm_free_vcpus(struct kvm *kvm) +static void kvm_unload_vcpu_mmus(struct kvm *kvm) { unsigned long i; struct kvm_vcpu *vcpu; - /* - * Unpin any mmu pages first. - */ kvm_for_each_vcpu(i, vcpu, kvm) { kvm_clear_async_pf_completion_queue(vcpu); kvm_unload_vcpu_mmu(vcpu); } - - kvm_destroy_vcpus(kvm); } void kvm_arch_sync_events(struct kvm *kvm) @@ -11935,11 +11930,12 @@ void kvm_arch_destroy_vm(struct kvm *kvm) __x86_set_memory_region(kvm, TSS_PRIVATE_MEMSLOT, 0, 0); mutex_unlock(&kvm->slots_lock); } + kvm_unload_vcpu_mmus(kvm); static_call_cond(kvm_x86_vm_destroy)(kvm); kvm_free_msr_filter(srcu_dereference_check(kvm->arch.msr_filter, &kvm->srcu, 1)); kvm_pic_destroy(kvm); kvm_ioapic_destroy(kvm); - kvm_free_vcpus(kvm); + kvm_destroy_vcpus(kvm); kvfree(rcu_dereference_check(kvm->arch.apic_map, 1)); kfree(srcu_dereference_check(kvm->arch.pmu_event_filter, &kvm->srcu, 1)); kvm_mmu_uninit_vm(kvm);

2 years, 6 months

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FAILED: patch "[PATCH] KVM: x86: Use __try_cmpxchg_user() to emulate atomic accesses" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 1c2361f667f3648855ceae25f1332c18413fdb9f Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 2 Feb 2022 00:49:44 +0000 Subject: [PATCH] KVM: x86: Use __try_cmpxchg_user() to emulate atomic accesses Use the recently introduce __try_cmpxchg_user() to emulate atomic guest accesses via the associated userspace address instead of mapping the backing pfn into kernel address space. Using kvm_vcpu_map() is unsafe as it does not coordinate with KVM's mmu_notifier to ensure the hva=>pfn translation isn't changed/unmapped in the memremap() path, i.e. when there's no struct page and thus no elevated refcount. Fixes: 42e35f8072c3 ("KVM/X86: Use kvm_vcpu_map in emulator_cmpxchg_emulated") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20220202004945.2540433-5-seanjc(a)google.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index fb8153d584c8..e5b0dd24b200 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7257,15 +7257,8 @@ static int emulator_write_emulated(struct x86_emulate_ctxt *ctxt, exception, &write_emultor); } -#define CMPXCHG_TYPE(t, ptr, old, new) \ - (cmpxchg((t *)(ptr), *(t *)(old), *(t *)(new)) == *(t *)(old)) - -#ifdef CONFIG_X86_64 -# define CMPXCHG64(ptr, old, new) CMPXCHG_TYPE(u64, ptr, old, new) -#else -# define CMPXCHG64(ptr, old, new) \ - (cmpxchg64((u64 *)(ptr), *(u64 *)(old), *(u64 *)(new)) == *(u64 *)(old)) -#endif +#define emulator_try_cmpxchg_user(t, ptr, old, new) \ + (__try_cmpxchg_user((t __user *)(ptr), (t *)(old), *(t *)(new), efault ## t)) static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt, unsigned long addr, @@ -7274,12 +7267,11 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt, unsigned int bytes, struct x86_exception *exception) { - struct kvm_host_map map; struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt); u64 page_line_mask; + unsigned long hva; gpa_t gpa; - char *kaddr; - bool exchanged; + int r; /* guests cmpxchg8b have to be emulated atomically */ if (bytes > 8 || (bytes & (bytes - 1))) @@ -7303,31 +7295,32 @@ static int emulator_cmpxchg_emulated(struct x86_emulate_ctxt *ctxt, if (((gpa + bytes - 1) & page_line_mask) != (gpa & page_line_mask)) goto emul_write; - if (kvm_vcpu_map(vcpu, gpa_to_gfn(gpa), &map)) + hva = kvm_vcpu_gfn_to_hva(vcpu, gpa_to_gfn(gpa)); + if (kvm_is_error_hva(addr)) goto emul_write; - kaddr = map.hva + offset_in_page(gpa); + hva += offset_in_page(gpa); switch (bytes) { case 1: - exchanged = CMPXCHG_TYPE(u8, kaddr, old, new); + r = emulator_try_cmpxchg_user(u8, hva, old, new); break; case 2: - exchanged = CMPXCHG_TYPE(u16, kaddr, old, new); + r = emulator_try_cmpxchg_user(u16, hva, old, new); break; case 4: - exchanged = CMPXCHG_TYPE(u32, kaddr, old, new); + r = emulator_try_cmpxchg_user(u32, hva, old, new); break; case 8: - exchanged = CMPXCHG64(kaddr, old, new); + r = emulator_try_cmpxchg_user(u64, hva, old, new); break; default: BUG(); } - kvm_vcpu_unmap(vcpu, &map, true); - - if (!exchanged) + if (r < 0) + goto emul_write; + if (r) return X86EMUL_CMPXCHG_FAILED; kvm_page_track_write(vcpu, gpa, new, bytes);

2 years, 6 months

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FAILED: patch "[PATCH] KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From f122dfe4476890d60b8c679128cd2259ec96a24c Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 2 Feb 2022 00:49:43 +0000 Subject: [PATCH] KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits Use the recently introduced __try_cmpxchg_user() to update guest PTE A/D bits instead of mapping the PTE into kernel address space. The VM_PFNMAP path is broken as it assumes that vm_pgoff is the base pfn of the mapped VMA range, which is conceptually wrong as vm_pgoff is the offset relative to the file and has nothing to do with the pfn. The horrific hack worked for the original use case (backing guest memory with /dev/mem), but leads to accessing "random" pfns for pretty much any other VM_PFNMAP case. Fixes: bd53cb35a3e9 ("X86/KVM: Handle PFNs outside of kernel reach when touching GPTEs") Debugged-by: Tadeusz Struk <tadeusz.struk(a)linaro.org> Tested-by: Tadeusz Struk <tadeusz.struk(a)linaro.org> Reported-by: syzbot+6cde2282daa792c49ab8(a)syzkaller.appspotmail.com Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20220202004945.2540433-4-seanjc(a)google.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 1dad8f3f2bb0..7d4377f1ef2a 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -144,42 +144,6 @@ static bool FNAME(is_rsvd_bits_set)(struct kvm_mmu *mmu, u64 gpte, int level) FNAME(is_bad_mt_xwr)(&mmu->guest_rsvd_check, gpte); } -static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, - pt_element_t __user *ptep_user, unsigned index, - pt_element_t orig_pte, pt_element_t new_pte) -{ - signed char r; - - if (!user_access_begin(ptep_user, sizeof(pt_element_t))) - return -EFAULT; - -#ifdef CMPXCHG - asm volatile("1:" LOCK_PREFIX CMPXCHG " %[new], %[ptr]\n" - "setnz %b[r]\n" - "2:" - _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %k[r]) - : [ptr] "+m" (*ptep_user), - [old] "+a" (orig_pte), - [r] "=q" (r) - : [new] "r" (new_pte) - : "memory"); -#else - asm volatile("1:" LOCK_PREFIX "cmpxchg8b %[ptr]\n" - "setnz %b[r]\n" - "2:" - _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %k[r]) - : [ptr] "+m" (*ptep_user), - [old] "+A" (orig_pte), - [r] "=q" (r) - : [new_lo] "b" ((u32)new_pte), - [new_hi] "c" ((u32)(new_pte >> 32)) - : "memory"); -#endif - - user_access_end(); - return r; -} - static bool FNAME(prefetch_invalid_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, u64 *spte, u64 gpte) @@ -278,7 +242,7 @@ static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu, if (unlikely(!walker->pte_writable[level - 1])) continue; - ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index, orig_pte, pte); + ret = __try_cmpxchg_user(ptep_user, &orig_pte, pte, fault); if (ret) return ret;

2 years, 6 months

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FAILED: patch "[PATCH] KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From f122dfe4476890d60b8c679128cd2259ec96a24c Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 2 Feb 2022 00:49:43 +0000 Subject: [PATCH] KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits Use the recently introduced __try_cmpxchg_user() to update guest PTE A/D bits instead of mapping the PTE into kernel address space. The VM_PFNMAP path is broken as it assumes that vm_pgoff is the base pfn of the mapped VMA range, which is conceptually wrong as vm_pgoff is the offset relative to the file and has nothing to do with the pfn. The horrific hack worked for the original use case (backing guest memory with /dev/mem), but leads to accessing "random" pfns for pretty much any other VM_PFNMAP case. Fixes: bd53cb35a3e9 ("X86/KVM: Handle PFNs outside of kernel reach when touching GPTEs") Debugged-by: Tadeusz Struk <tadeusz.struk(a)linaro.org> Tested-by: Tadeusz Struk <tadeusz.struk(a)linaro.org> Reported-by: syzbot+6cde2282daa792c49ab8(a)syzkaller.appspotmail.com Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20220202004945.2540433-4-seanjc(a)google.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 1dad8f3f2bb0..7d4377f1ef2a 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -144,42 +144,6 @@ static bool FNAME(is_rsvd_bits_set)(struct kvm_mmu *mmu, u64 gpte, int level) FNAME(is_bad_mt_xwr)(&mmu->guest_rsvd_check, gpte); } -static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, - pt_element_t __user *ptep_user, unsigned index, - pt_element_t orig_pte, pt_element_t new_pte) -{ - signed char r; - - if (!user_access_begin(ptep_user, sizeof(pt_element_t))) - return -EFAULT; - -#ifdef CMPXCHG - asm volatile("1:" LOCK_PREFIX CMPXCHG " %[new], %[ptr]\n" - "setnz %b[r]\n" - "2:" - _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %k[r]) - : [ptr] "+m" (*ptep_user), - [old] "+a" (orig_pte), - [r] "=q" (r) - : [new] "r" (new_pte) - : "memory"); -#else - asm volatile("1:" LOCK_PREFIX "cmpxchg8b %[ptr]\n" - "setnz %b[r]\n" - "2:" - _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %k[r]) - : [ptr] "+m" (*ptep_user), - [old] "+A" (orig_pte), - [r] "=q" (r) - : [new_lo] "b" ((u32)new_pte), - [new_hi] "c" ((u32)(new_pte >> 32)) - : "memory"); -#endif - - user_access_end(); - return r; -} - static bool FNAME(prefetch_invalid_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, u64 *spte, u64 gpte) @@ -278,7 +242,7 @@ static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu, if (unlikely(!walker->pte_writable[level - 1])) continue; - ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index, orig_pte, pte); + ret = __try_cmpxchg_user(ptep_user, &orig_pte, pte, fault); if (ret) return ret;

2 years, 6 months

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FAILED: patch "[PATCH] KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From f122dfe4476890d60b8c679128cd2259ec96a24c Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 2 Feb 2022 00:49:43 +0000 Subject: [PATCH] KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits Use the recently introduced __try_cmpxchg_user() to update guest PTE A/D bits instead of mapping the PTE into kernel address space. The VM_PFNMAP path is broken as it assumes that vm_pgoff is the base pfn of the mapped VMA range, which is conceptually wrong as vm_pgoff is the offset relative to the file and has nothing to do with the pfn. The horrific hack worked for the original use case (backing guest memory with /dev/mem), but leads to accessing "random" pfns for pretty much any other VM_PFNMAP case. Fixes: bd53cb35a3e9 ("X86/KVM: Handle PFNs outside of kernel reach when touching GPTEs") Debugged-by: Tadeusz Struk <tadeusz.struk(a)linaro.org> Tested-by: Tadeusz Struk <tadeusz.struk(a)linaro.org> Reported-by: syzbot+6cde2282daa792c49ab8(a)syzkaller.appspotmail.com Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20220202004945.2540433-4-seanjc(a)google.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 1dad8f3f2bb0..7d4377f1ef2a 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -144,42 +144,6 @@ static bool FNAME(is_rsvd_bits_set)(struct kvm_mmu *mmu, u64 gpte, int level) FNAME(is_bad_mt_xwr)(&mmu->guest_rsvd_check, gpte); } -static int FNAME(cmpxchg_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, - pt_element_t __user *ptep_user, unsigned index, - pt_element_t orig_pte, pt_element_t new_pte) -{ - signed char r; - - if (!user_access_begin(ptep_user, sizeof(pt_element_t))) - return -EFAULT; - -#ifdef CMPXCHG - asm volatile("1:" LOCK_PREFIX CMPXCHG " %[new], %[ptr]\n" - "setnz %b[r]\n" - "2:" - _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %k[r]) - : [ptr] "+m" (*ptep_user), - [old] "+a" (orig_pte), - [r] "=q" (r) - : [new] "r" (new_pte) - : "memory"); -#else - asm volatile("1:" LOCK_PREFIX "cmpxchg8b %[ptr]\n" - "setnz %b[r]\n" - "2:" - _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %k[r]) - : [ptr] "+m" (*ptep_user), - [old] "+A" (orig_pte), - [r] "=q" (r) - : [new_lo] "b" ((u32)new_pte), - [new_hi] "c" ((u32)(new_pte >> 32)) - : "memory"); -#endif - - user_access_end(); - return r; -} - static bool FNAME(prefetch_invalid_gpte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, u64 *spte, u64 gpte) @@ -278,7 +242,7 @@ static int FNAME(update_accessed_dirty_bits)(struct kvm_vcpu *vcpu, if (unlikely(!walker->pte_writable[level - 1])) continue; - ret = FNAME(cmpxchg_gpte)(vcpu, mmu, ptep_user, index, orig_pte, pte); + ret = __try_cmpxchg_user(ptep_user, &orig_pte, pte, fault); if (ret) return ret;

2 years, 6 months

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