May 2021 - Linux-stable-mirror

FAILED: patch "[PATCH] KVM: x86: Remove emulator's broken checks on CR0/CR3/CR4" 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 d0fe7b6404408835ed60232cb3bf28324b2f95db Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 21 Apr 2021 19:21:20 -0700 Subject: [PATCH] KVM: x86: Remove emulator's broken checks on CR0/CR3/CR4 loads Remove the emulator's checks for illegal CR0, CR3, and CR4 values, as the checks are redundant, outdated, and in the case of SEV's C-bit, broken. The emulator manually calculates MAXPHYADDR from CPUID and neglects to mask off the C-bit. For all other checks, kvm_set_cr*() are a superset of the emulator checks, e.g. see CR4.LA57. Fixes: a780a3ea6282 ("KVM: X86: Fix reserved bits check for MOV to CR3") Cc: Babu Moger <babu.moger(a)amd.com> Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210422022128.3464144-2-seanjc(a)google.com> Cc: stable(a)vger.kernel.org [Unify check_cr_read and check_cr_write. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index f7970ba6219f..abd9a4db11a8 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4220,7 +4220,7 @@ static bool valid_cr(int nr) } } -static int check_cr_read(struct x86_emulate_ctxt *ctxt) +static int check_cr_access(struct x86_emulate_ctxt *ctxt) { if (!valid_cr(ctxt->modrm_reg)) return emulate_ud(ctxt); @@ -4228,80 +4228,6 @@ static int check_cr_read(struct x86_emulate_ctxt *ctxt) return X86EMUL_CONTINUE; } -static int check_cr_write(struct x86_emulate_ctxt *ctxt) -{ - u64 new_val = ctxt->src.val64; - int cr = ctxt->modrm_reg; - u64 efer = 0; - - static u64 cr_reserved_bits[] = { - 0xffffffff00000000ULL, - 0, 0, 0, /* CR3 checked later */ - CR4_RESERVED_BITS, - 0, 0, 0, - CR8_RESERVED_BITS, - }; - - if (!valid_cr(cr)) - return emulate_ud(ctxt); - - if (new_val & cr_reserved_bits[cr]) - return emulate_gp(ctxt, 0); - - switch (cr) { - case 0: { - u64 cr4; - if (((new_val & X86_CR0_PG) && !(new_val & X86_CR0_PE)) || - ((new_val & X86_CR0_NW) && !(new_val & X86_CR0_CD))) - return emulate_gp(ctxt, 0); - - cr4 = ctxt->ops->get_cr(ctxt, 4); - ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); - - if ((new_val & X86_CR0_PG) && (efer & EFER_LME) && - !(cr4 & X86_CR4_PAE)) - return emulate_gp(ctxt, 0); - - break; - } - case 3: { - u64 rsvd = 0; - - ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); - if (efer & EFER_LMA) { - u64 maxphyaddr; - u32 eax, ebx, ecx, edx; - - eax = 0x80000008; - ecx = 0; - if (ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, - &edx, true)) - maxphyaddr = eax & 0xff; - else - maxphyaddr = 36; - rsvd = rsvd_bits(maxphyaddr, 63); - if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PCIDE) - rsvd &= ~X86_CR3_PCID_NOFLUSH; - } - - if (new_val & rsvd) - return emulate_gp(ctxt, 0); - - break; - } - case 4: { - ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); - - if ((efer & EFER_LMA) && !(new_val & X86_CR4_PAE)) - return emulate_gp(ctxt, 0); - - break; - } - } - - return X86EMUL_CONTINUE; -} - static int check_dr7_gd(struct x86_emulate_ctxt *ctxt) { unsigned long dr7; @@ -4841,10 +4767,10 @@ static const struct opcode twobyte_table[256] = { D(ImplicitOps | ModRM | SrcMem | NoAccess), /* 8 * reserved NOP */ D(ImplicitOps | ModRM | SrcMem | NoAccess), /* NOP + 7 * reserved NOP */ /* 0x20 - 0x2F */ - DIP(ModRM | DstMem | Priv | Op3264 | NoMod, cr_read, check_cr_read), + DIP(ModRM | DstMem | Priv | Op3264 | NoMod, cr_read, check_cr_access), DIP(ModRM | DstMem | Priv | Op3264 | NoMod, dr_read, check_dr_read), IIP(ModRM | SrcMem | Priv | Op3264 | NoMod, em_cr_write, cr_write, - check_cr_write), + check_cr_access), IIP(ModRM | SrcMem | Priv | Op3264 | NoMod, em_dr_write, dr_write, check_dr_write), N, N, N, N,

3 years, 8 months

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FAILED: patch "[PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode" 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 886bbcc7a523b8d4fac60f1015d2e0fcad50db82 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 21 Apr 2021 19:21:21 -0700 Subject: [PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode Check CR3 for an invalid GPA even if the vCPU isn't in long mode. For bigger emulation flows, notably RSM, the vCPU mode may not be accurate if CR0/CR4 are loaded after CR3. For MOV CR3 and similar flows, the caller is responsible for truncating the value. Fixes: 660a5d517aaa ("KVM: x86: save/load state on SMM switch") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210422022128.3464144-3-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 4c9c9592a437..3010284dc59b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1077,10 +1077,15 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) return 0; } - if (is_long_mode(vcpu) && kvm_vcpu_is_illegal_gpa(vcpu, cr3)) + /* + * Do not condition the GPA check on long mode, this helper is used to + * stuff CR3, e.g. for RSM emulation, and there is no guarantee that + * the current vCPU mode is accurate. + */ + if (kvm_vcpu_is_illegal_gpa(vcpu, cr3)) return 1; - else if (is_pae_paging(vcpu) && - !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) + + if (is_pae_paging(vcpu) && !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) return 1; kvm_mmu_new_pgd(vcpu, cr3, skip_tlb_flush, skip_tlb_flush);

3 years, 8 months

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FAILED: patch "[PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode" failed to apply to 5.11-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.11-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 886bbcc7a523b8d4fac60f1015d2e0fcad50db82 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 21 Apr 2021 19:21:21 -0700 Subject: [PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode Check CR3 for an invalid GPA even if the vCPU isn't in long mode. For bigger emulation flows, notably RSM, the vCPU mode may not be accurate if CR0/CR4 are loaded after CR3. For MOV CR3 and similar flows, the caller is responsible for truncating the value. Fixes: 660a5d517aaa ("KVM: x86: save/load state on SMM switch") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210422022128.3464144-3-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 4c9c9592a437..3010284dc59b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1077,10 +1077,15 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) return 0; } - if (is_long_mode(vcpu) && kvm_vcpu_is_illegal_gpa(vcpu, cr3)) + /* + * Do not condition the GPA check on long mode, this helper is used to + * stuff CR3, e.g. for RSM emulation, and there is no guarantee that + * the current vCPU mode is accurate. + */ + if (kvm_vcpu_is_illegal_gpa(vcpu, cr3)) return 1; - else if (is_pae_paging(vcpu) && - !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) + + if (is_pae_paging(vcpu) && !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) return 1; kvm_mmu_new_pgd(vcpu, cr3, skip_tlb_flush, skip_tlb_flush);

3 years, 8 months

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FAILED: patch "[PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode" 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 886bbcc7a523b8d4fac60f1015d2e0fcad50db82 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 21 Apr 2021 19:21:21 -0700 Subject: [PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode Check CR3 for an invalid GPA even if the vCPU isn't in long mode. For bigger emulation flows, notably RSM, the vCPU mode may not be accurate if CR0/CR4 are loaded after CR3. For MOV CR3 and similar flows, the caller is responsible for truncating the value. Fixes: 660a5d517aaa ("KVM: x86: save/load state on SMM switch") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210422022128.3464144-3-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 4c9c9592a437..3010284dc59b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1077,10 +1077,15 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) return 0; } - if (is_long_mode(vcpu) && kvm_vcpu_is_illegal_gpa(vcpu, cr3)) + /* + * Do not condition the GPA check on long mode, this helper is used to + * stuff CR3, e.g. for RSM emulation, and there is no guarantee that + * the current vCPU mode is accurate. + */ + if (kvm_vcpu_is_illegal_gpa(vcpu, cr3)) return 1; - else if (is_pae_paging(vcpu) && - !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) + + if (is_pae_paging(vcpu) && !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) return 1; kvm_mmu_new_pgd(vcpu, cr3, skip_tlb_flush, skip_tlb_flush);

3 years, 8 months

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FAILED: patch "[PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode" 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 886bbcc7a523b8d4fac60f1015d2e0fcad50db82 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 21 Apr 2021 19:21:21 -0700 Subject: [PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode Check CR3 for an invalid GPA even if the vCPU isn't in long mode. For bigger emulation flows, notably RSM, the vCPU mode may not be accurate if CR0/CR4 are loaded after CR3. For MOV CR3 and similar flows, the caller is responsible for truncating the value. Fixes: 660a5d517aaa ("KVM: x86: save/load state on SMM switch") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210422022128.3464144-3-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 4c9c9592a437..3010284dc59b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1077,10 +1077,15 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) return 0; } - if (is_long_mode(vcpu) && kvm_vcpu_is_illegal_gpa(vcpu, cr3)) + /* + * Do not condition the GPA check on long mode, this helper is used to + * stuff CR3, e.g. for RSM emulation, and there is no guarantee that + * the current vCPU mode is accurate. + */ + if (kvm_vcpu_is_illegal_gpa(vcpu, cr3)) return 1; - else if (is_pae_paging(vcpu) && - !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) + + if (is_pae_paging(vcpu) && !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) return 1; kvm_mmu_new_pgd(vcpu, cr3, skip_tlb_flush, skip_tlb_flush);

3 years, 8 months

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FAILED: patch "[PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode" 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 886bbcc7a523b8d4fac60f1015d2e0fcad50db82 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 21 Apr 2021 19:21:21 -0700 Subject: [PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode Check CR3 for an invalid GPA even if the vCPU isn't in long mode. For bigger emulation flows, notably RSM, the vCPU mode may not be accurate if CR0/CR4 are loaded after CR3. For MOV CR3 and similar flows, the caller is responsible for truncating the value. Fixes: 660a5d517aaa ("KVM: x86: save/load state on SMM switch") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210422022128.3464144-3-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 4c9c9592a437..3010284dc59b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1077,10 +1077,15 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) return 0; } - if (is_long_mode(vcpu) && kvm_vcpu_is_illegal_gpa(vcpu, cr3)) + /* + * Do not condition the GPA check on long mode, this helper is used to + * stuff CR3, e.g. for RSM emulation, and there is no guarantee that + * the current vCPU mode is accurate. + */ + if (kvm_vcpu_is_illegal_gpa(vcpu, cr3)) return 1; - else if (is_pae_paging(vcpu) && - !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) + + if (is_pae_paging(vcpu) && !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) return 1; kvm_mmu_new_pgd(vcpu, cr3, skip_tlb_flush, skip_tlb_flush);

3 years, 8 months

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FAILED: patch "[PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode" failed to apply to 4.9-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.9-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 886bbcc7a523b8d4fac60f1015d2e0fcad50db82 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 21 Apr 2021 19:21:21 -0700 Subject: [PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode Check CR3 for an invalid GPA even if the vCPU isn't in long mode. For bigger emulation flows, notably RSM, the vCPU mode may not be accurate if CR0/CR4 are loaded after CR3. For MOV CR3 and similar flows, the caller is responsible for truncating the value. Fixes: 660a5d517aaa ("KVM: x86: save/load state on SMM switch") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210422022128.3464144-3-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 4c9c9592a437..3010284dc59b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1077,10 +1077,15 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) return 0; } - if (is_long_mode(vcpu) && kvm_vcpu_is_illegal_gpa(vcpu, cr3)) + /* + * Do not condition the GPA check on long mode, this helper is used to + * stuff CR3, e.g. for RSM emulation, and there is no guarantee that + * the current vCPU mode is accurate. + */ + if (kvm_vcpu_is_illegal_gpa(vcpu, cr3)) return 1; - else if (is_pae_paging(vcpu) && - !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) + + if (is_pae_paging(vcpu) && !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) return 1; kvm_mmu_new_pgd(vcpu, cr3, skip_tlb_flush, skip_tlb_flush);

3 years, 8 months

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FAILED: patch "[PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode" failed to apply to 4.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.4-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 886bbcc7a523b8d4fac60f1015d2e0fcad50db82 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Wed, 21 Apr 2021 19:21:21 -0700 Subject: [PATCH] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode Check CR3 for an invalid GPA even if the vCPU isn't in long mode. For bigger emulation flows, notably RSM, the vCPU mode may not be accurate if CR0/CR4 are loaded after CR3. For MOV CR3 and similar flows, the caller is responsible for truncating the value. Fixes: 660a5d517aaa ("KVM: x86: save/load state on SMM switch") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210422022128.3464144-3-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 4c9c9592a437..3010284dc59b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1077,10 +1077,15 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) return 0; } - if (is_long_mode(vcpu) && kvm_vcpu_is_illegal_gpa(vcpu, cr3)) + /* + * Do not condition the GPA check on long mode, this helper is used to + * stuff CR3, e.g. for RSM emulation, and there is no guarantee that + * the current vCPU mode is accurate. + */ + if (kvm_vcpu_is_illegal_gpa(vcpu, cr3)) return 1; - else if (is_pae_paging(vcpu) && - !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) + + if (is_pae_paging(vcpu) && !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) return 1; kvm_mmu_new_pgd(vcpu, cr3, skip_tlb_flush, skip_tlb_flush);

3 years, 8 months

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FAILED: patch "[PATCH] KVM: x86/mmu: Alloc page for PDPTEs when shadowing 32-bit NPT" 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 04d45551a1eefbea42655da52f56e846c0af721a Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Thu, 4 Mar 2021 17:10:46 -0800 Subject: [PATCH] KVM: x86/mmu: Alloc page for PDPTEs when shadowing 32-bit NPT with 64-bit Allocate the so called pae_root page on-demand, along with the lm_root page, when shadowing 32-bit NPT with 64-bit NPT, i.e. when running a 32-bit L1. KVM currently only allocates the page when NPT is disabled, or when L0 is 32-bit (using PAE paging). Note, there is an existing memory leak involving the MMU roots, as KVM fails to free the PAE roots on failure. This will be addressed in a future commit. Fixes: ee6268ba3a68 ("KVM: x86: Skip pae_root shadow allocation if tdp enabled") Fixes: b6b80c78af83 ("KVM: x86/mmu: Allocate PAE root array when using SVM's 32-bit NPT") Cc: stable(a)vger.kernel.org Reviewed-by: Ben Gardon <bgardon(a)google.com> Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210305011101.3597423-3-seanjc(a)google.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index d75524bc8423..b52bd620d1e5 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3193,14 +3193,14 @@ void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, if (mmu->shadow_root_level >= PT64_ROOT_4LEVEL && (mmu->root_level >= PT64_ROOT_4LEVEL || mmu->direct_map)) { mmu_free_root_page(kvm, &mmu->root_hpa, &invalid_list); - } else { + } else if (mmu->pae_root) { for (i = 0; i < 4; ++i) if (mmu->pae_root[i] != 0) mmu_free_root_page(kvm, &mmu->pae_root[i], &invalid_list); - mmu->root_hpa = INVALID_PAGE; } + mmu->root_hpa = INVALID_PAGE; mmu->root_pgd = 0; } @@ -3312,9 +3312,23 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) * the shadow page table may be a PAE or a long mode page table. */ pm_mask = PT_PRESENT_MASK; - if (vcpu->arch.mmu->shadow_root_level == PT64_ROOT_4LEVEL) + if (vcpu->arch.mmu->shadow_root_level == PT64_ROOT_4LEVEL) { pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK; + /* + * Allocate the page for the PDPTEs when shadowing 32-bit NPT + * with 64-bit only when needed. Unlike 32-bit NPT, it doesn't + * need to be in low mem. See also lm_root below. + */ + if (!vcpu->arch.mmu->pae_root) { + WARN_ON_ONCE(!tdp_enabled); + + vcpu->arch.mmu->pae_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT); + if (!vcpu->arch.mmu->pae_root) + return -ENOMEM; + } + } + for (i = 0; i < 4; ++i) { MMU_WARN_ON(VALID_PAGE(vcpu->arch.mmu->pae_root[i])); if (vcpu->arch.mmu->root_level == PT32E_ROOT_LEVEL) { @@ -3337,21 +3351,19 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) vcpu->arch.mmu->root_hpa = __pa(vcpu->arch.mmu->pae_root); /* - * If we shadow a 32 bit page table with a long mode page - * table we enter this path. + * When shadowing 32-bit or PAE NPT with 64-bit NPT, the PML4 and PDP + * tables are allocated and initialized at MMU creation as there is no + * equivalent level in the guest's NPT to shadow. Allocate the tables + * on demand, as running a 32-bit L1 VMM is very rare. The PDP is + * handled above (to share logic with PAE), deal with the PML4 here. */ if (vcpu->arch.mmu->shadow_root_level == PT64_ROOT_4LEVEL) { if (vcpu->arch.mmu->lm_root == NULL) { - /* - * The additional page necessary for this is only - * allocated on demand. - */ - u64 *lm_root; lm_root = (void*)get_zeroed_page(GFP_KERNEL_ACCOUNT); - if (lm_root == NULL) - return 1; + if (!lm_root) + return -ENOMEM; lm_root[0] = __pa(vcpu->arch.mmu->pae_root) | pm_mask; @@ -5240,9 +5252,11 @@ static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu) * while the PDP table is a per-vCPU construct that's allocated at MMU * creation. When emulating 32-bit mode, cr3 is only 32 bits even on * x86_64. Therefore we need to allocate the PDP table in the first - * 4GB of memory, which happens to fit the DMA32 zone. Except for - * SVM's 32-bit NPT support, TDP paging doesn't use PAE paging and can - * skip allocating the PDP table. + * 4GB of memory, which happens to fit the DMA32 zone. TDP paging + * generally doesn't use PAE paging and can skip allocating the PDP + * table. The main exception, handled here, is SVM's 32-bit NPT. The + * other exception is for shadowing L1's 32-bit or PAE NPT on 64-bit + * KVM; that horror is handled on-demand by mmu_alloc_shadow_roots(). */ if (tdp_enabled && kvm_mmu_get_tdp_level(vcpu) > PT32E_ROOT_LEVEL) return 0;

3 years, 8 months

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FAILED: patch "[PATCH] KVM: x86/mmu: Alloc page for PDPTEs when shadowing 32-bit NPT" 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 04d45551a1eefbea42655da52f56e846c0af721a Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Thu, 4 Mar 2021 17:10:46 -0800 Subject: [PATCH] KVM: x86/mmu: Alloc page for PDPTEs when shadowing 32-bit NPT with 64-bit Allocate the so called pae_root page on-demand, along with the lm_root page, when shadowing 32-bit NPT with 64-bit NPT, i.e. when running a 32-bit L1. KVM currently only allocates the page when NPT is disabled, or when L0 is 32-bit (using PAE paging). Note, there is an existing memory leak involving the MMU roots, as KVM fails to free the PAE roots on failure. This will be addressed in a future commit. Fixes: ee6268ba3a68 ("KVM: x86: Skip pae_root shadow allocation if tdp enabled") Fixes: b6b80c78af83 ("KVM: x86/mmu: Allocate PAE root array when using SVM's 32-bit NPT") Cc: stable(a)vger.kernel.org Reviewed-by: Ben Gardon <bgardon(a)google.com> Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210305011101.3597423-3-seanjc(a)google.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index d75524bc8423..b52bd620d1e5 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3193,14 +3193,14 @@ void kvm_mmu_free_roots(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, if (mmu->shadow_root_level >= PT64_ROOT_4LEVEL && (mmu->root_level >= PT64_ROOT_4LEVEL || mmu->direct_map)) { mmu_free_root_page(kvm, &mmu->root_hpa, &invalid_list); - } else { + } else if (mmu->pae_root) { for (i = 0; i < 4; ++i) if (mmu->pae_root[i] != 0) mmu_free_root_page(kvm, &mmu->pae_root[i], &invalid_list); - mmu->root_hpa = INVALID_PAGE; } + mmu->root_hpa = INVALID_PAGE; mmu->root_pgd = 0; } @@ -3312,9 +3312,23 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) * the shadow page table may be a PAE or a long mode page table. */ pm_mask = PT_PRESENT_MASK; - if (vcpu->arch.mmu->shadow_root_level == PT64_ROOT_4LEVEL) + if (vcpu->arch.mmu->shadow_root_level == PT64_ROOT_4LEVEL) { pm_mask |= PT_ACCESSED_MASK | PT_WRITABLE_MASK | PT_USER_MASK; + /* + * Allocate the page for the PDPTEs when shadowing 32-bit NPT + * with 64-bit only when needed. Unlike 32-bit NPT, it doesn't + * need to be in low mem. See also lm_root below. + */ + if (!vcpu->arch.mmu->pae_root) { + WARN_ON_ONCE(!tdp_enabled); + + vcpu->arch.mmu->pae_root = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT); + if (!vcpu->arch.mmu->pae_root) + return -ENOMEM; + } + } + for (i = 0; i < 4; ++i) { MMU_WARN_ON(VALID_PAGE(vcpu->arch.mmu->pae_root[i])); if (vcpu->arch.mmu->root_level == PT32E_ROOT_LEVEL) { @@ -3337,21 +3351,19 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) vcpu->arch.mmu->root_hpa = __pa(vcpu->arch.mmu->pae_root); /* - * If we shadow a 32 bit page table with a long mode page - * table we enter this path. + * When shadowing 32-bit or PAE NPT with 64-bit NPT, the PML4 and PDP + * tables are allocated and initialized at MMU creation as there is no + * equivalent level in the guest's NPT to shadow. Allocate the tables + * on demand, as running a 32-bit L1 VMM is very rare. The PDP is + * handled above (to share logic with PAE), deal with the PML4 here. */ if (vcpu->arch.mmu->shadow_root_level == PT64_ROOT_4LEVEL) { if (vcpu->arch.mmu->lm_root == NULL) { - /* - * The additional page necessary for this is only - * allocated on demand. - */ - u64 *lm_root; lm_root = (void*)get_zeroed_page(GFP_KERNEL_ACCOUNT); - if (lm_root == NULL) - return 1; + if (!lm_root) + return -ENOMEM; lm_root[0] = __pa(vcpu->arch.mmu->pae_root) | pm_mask; @@ -5240,9 +5252,11 @@ static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu) * while the PDP table is a per-vCPU construct that's allocated at MMU * creation. When emulating 32-bit mode, cr3 is only 32 bits even on * x86_64. Therefore we need to allocate the PDP table in the first - * 4GB of memory, which happens to fit the DMA32 zone. Except for - * SVM's 32-bit NPT support, TDP paging doesn't use PAE paging and can - * skip allocating the PDP table. + * 4GB of memory, which happens to fit the DMA32 zone. TDP paging + * generally doesn't use PAE paging and can skip allocating the PDP + * table. The main exception, handled here, is SVM's 32-bit NPT. The + * other exception is for shadowing L1's 32-bit or PAE NPT on 64-bit + * KVM; that horror is handled on-demand by mmu_alloc_shadow_roots(). */ if (tdp_enabled && kvm_mmu_get_tdp_level(vcpu) > PT32E_ROOT_LEVEL) return 0;

3 years, 8 months

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