July 2021 - Linux-stable-mirror

FAILED: patch "[PATCH] KVM: x86: Force all MMUs to reinitialize if guest CPUID is" 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 49c6f8756cdffeb9af1fbcb86bacacced26465d7 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Tue, 22 Jun 2021 10:56:51 -0700 Subject: [PATCH] KVM: x86: Force all MMUs to reinitialize if guest CPUID is modified Invalidate all MMUs' roles after a CPUID update to force reinitizliation of the MMU context/helpers. Despite the efforts of commit de3ccd26fafc ("KVM: MMU: record maximum physical address width in kvm_mmu_extended_role"), there are still a handful of CPUID-based properties that affect MMU behavior but are not incorporated into mmu_role. E.g. 1gb hugepage support, AMD vs. Intel handling of bit 8, and SEV's C-Bit location all factor into the guest's reserved PTE bits. The obvious alternative would be to add all such properties to mmu_role, but doing so provides no benefit over simply forcing a reinitialization on every CPUID update, as setting guest CPUID is a rare operation. Note, reinitializing all MMUs after a CPUID update does not fix all of KVM's woes. Specifically, kvm_mmu_page_role doesn't track the CPUID properties, which means that a vCPU can reuse shadow pages that should not exist for the new vCPU model, e.g. that map GPAs that are now illegal (due to MAXPHYADDR changes) or that set bits that are now reserved (PAGE_SIZE for 1gb pages), etc... Tracking the relevant CPUID properties in kvm_mmu_page_role would address the majority of problems, but fully tracking that much state in the shadow page role comes with an unpalatable cost as it would require a non-trivial increase in KVM's memory footprint. The GBPAGES case is even worse, as neither Intel nor AMD provides a way to disable 1gb hugepage support in the hardware page walker, i.e. it's a virtualization hole that can't be closed when using TDP. In other words, resetting the MMU after a CPUID update is largely a superficial fix. But, it will allow reverting the tracking of MAXPHYADDR in the mmu_role, and that case in particular needs to mostly work because KVM's shadow_root_level depends on guest MAXPHYADDR when 5-level paging is supported. For cases where KVM botches guest behavior, the damage is limited to that guest. But for the shadow_root_level, a misconfigured MMU can cause KVM to incorrectly access memory, e.g. due to walking off the end of its shadow page tables. Fixes: 7dcd57552008 ("x86/kvm/mmu: check if tdp/shadow MMU reconfiguration is needed") Cc: Yu Zhang <yu.c.zhang(a)linux.intel.com> Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210622175739.3610207-7-seanjc(a)google.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index a474cd13b0c8..f1e4d5f2bf8d 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1496,6 +1496,7 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu); void kvm_mmu_init_vm(struct kvm *kvm); void kvm_mmu_uninit_vm(struct kvm *kvm); +void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu); void kvm_mmu_reset_context(struct kvm_vcpu *vcpu); void kvm_mmu_slot_remove_write_access(struct kvm *kvm, struct kvm_memory_slot *memslot, diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index b4da665bb892..c42613cfb5ba 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -202,10 +202,10 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) static_call(kvm_x86_vcpu_after_set_cpuid)(vcpu); /* - * Except for the MMU, which needs to be reset after any vendor - * specific adjustments to the reserved GPA bits. + * Except for the MMU, which needs to do its thing any vendor specific + * adjustments to the reserved GPA bits. */ - kvm_mmu_reset_context(vcpu); + kvm_mmu_after_set_cpuid(vcpu); } static int is_efer_nx(void) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index fa35762f325c..1ab3fdb1f2e4 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4903,6 +4903,18 @@ kvm_mmu_calc_root_page_role(struct kvm_vcpu *vcpu) return role.base; } +void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu) +{ + /* + * Invalidate all MMU roles to force them to reinitialize as CPUID + * information is factored into reserved bit calculations. + */ + vcpu->arch.root_mmu.mmu_role.ext.valid = 0; + vcpu->arch.guest_mmu.mmu_role.ext.valid = 0; + vcpu->arch.nested_mmu.mmu_role.ext.valid = 0; + kvm_mmu_reset_context(vcpu); +} + void kvm_mmu_reset_context(struct kvm_vcpu *vcpu) { kvm_mmu_unload(vcpu);

3 years, 2 months

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FAILED: patch "[PATCH] KVM: x86: Force all MMUs to reinitialize if guest CPUID is" 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 49c6f8756cdffeb9af1fbcb86bacacced26465d7 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Tue, 22 Jun 2021 10:56:51 -0700 Subject: [PATCH] KVM: x86: Force all MMUs to reinitialize if guest CPUID is modified Invalidate all MMUs' roles after a CPUID update to force reinitizliation of the MMU context/helpers. Despite the efforts of commit de3ccd26fafc ("KVM: MMU: record maximum physical address width in kvm_mmu_extended_role"), there are still a handful of CPUID-based properties that affect MMU behavior but are not incorporated into mmu_role. E.g. 1gb hugepage support, AMD vs. Intel handling of bit 8, and SEV's C-Bit location all factor into the guest's reserved PTE bits. The obvious alternative would be to add all such properties to mmu_role, but doing so provides no benefit over simply forcing a reinitialization on every CPUID update, as setting guest CPUID is a rare operation. Note, reinitializing all MMUs after a CPUID update does not fix all of KVM's woes. Specifically, kvm_mmu_page_role doesn't track the CPUID properties, which means that a vCPU can reuse shadow pages that should not exist for the new vCPU model, e.g. that map GPAs that are now illegal (due to MAXPHYADDR changes) or that set bits that are now reserved (PAGE_SIZE for 1gb pages), etc... Tracking the relevant CPUID properties in kvm_mmu_page_role would address the majority of problems, but fully tracking that much state in the shadow page role comes with an unpalatable cost as it would require a non-trivial increase in KVM's memory footprint. The GBPAGES case is even worse, as neither Intel nor AMD provides a way to disable 1gb hugepage support in the hardware page walker, i.e. it's a virtualization hole that can't be closed when using TDP. In other words, resetting the MMU after a CPUID update is largely a superficial fix. But, it will allow reverting the tracking of MAXPHYADDR in the mmu_role, and that case in particular needs to mostly work because KVM's shadow_root_level depends on guest MAXPHYADDR when 5-level paging is supported. For cases where KVM botches guest behavior, the damage is limited to that guest. But for the shadow_root_level, a misconfigured MMU can cause KVM to incorrectly access memory, e.g. due to walking off the end of its shadow page tables. Fixes: 7dcd57552008 ("x86/kvm/mmu: check if tdp/shadow MMU reconfiguration is needed") Cc: Yu Zhang <yu.c.zhang(a)linux.intel.com> Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210622175739.3610207-7-seanjc(a)google.com> Signed-off-by: Paolo Bonzini <pbonzini(a)redhat.com> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index a474cd13b0c8..f1e4d5f2bf8d 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1496,6 +1496,7 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu); void kvm_mmu_init_vm(struct kvm *kvm); void kvm_mmu_uninit_vm(struct kvm *kvm); +void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu); void kvm_mmu_reset_context(struct kvm_vcpu *vcpu); void kvm_mmu_slot_remove_write_access(struct kvm *kvm, struct kvm_memory_slot *memslot, diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index b4da665bb892..c42613cfb5ba 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -202,10 +202,10 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) static_call(kvm_x86_vcpu_after_set_cpuid)(vcpu); /* - * Except for the MMU, which needs to be reset after any vendor - * specific adjustments to the reserved GPA bits. + * Except for the MMU, which needs to do its thing any vendor specific + * adjustments to the reserved GPA bits. */ - kvm_mmu_reset_context(vcpu); + kvm_mmu_after_set_cpuid(vcpu); } static int is_efer_nx(void) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index fa35762f325c..1ab3fdb1f2e4 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4903,6 +4903,18 @@ kvm_mmu_calc_root_page_role(struct kvm_vcpu *vcpu) return role.base; } +void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu) +{ + /* + * Invalidate all MMU roles to force them to reinitialize as CPUID + * information is factored into reserved bit calculations. + */ + vcpu->arch.root_mmu.mmu_role.ext.valid = 0; + vcpu->arch.guest_mmu.mmu_role.ext.valid = 0; + vcpu->arch.nested_mmu.mmu_role.ext.valid = 0; + kvm_mmu_reset_context(vcpu); +} + void kvm_mmu_reset_context(struct kvm_vcpu *vcpu) { kvm_mmu_unload(vcpu);

3 years, 2 months

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FAILED: patch "[PATCH] KVM: x86/mmu: Use MMU's role to detect CR4.SMEP value in" 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 ef318b9edf66a082f23d00d79b70c17b4c055a26 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Tue, 22 Jun 2021 10:56:49 -0700 Subject: [PATCH] KVM: x86/mmu: Use MMU's role to detect CR4.SMEP value in nested NPT walk Use the MMU's role to get its effective SMEP value when injecting a fault into the guest. When walking L1's (nested) NPT while L2 is active, vCPU state will reflect L2, whereas NPT uses the host's (L1 in this case) CR0, CR4, EFER, etc... If L1 and L2 have different settings for SMEP and L1 does not have EFER.NX=1, this can result in an incorrect PFEC.FETCH when injecting #NPF. Fixes: e57d4a356ad3 ("KVM: Add instruction fetch checking when walking guest page table") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210622175739.3610207-5-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 823a5919f9fa..52fffd68b522 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -471,8 +471,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, error: errcode |= write_fault | user_fault; - if (fetch_fault && (mmu->nx || - kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))) + if (fetch_fault && (mmu->nx || mmu->mmu_role.ext.cr4_smep)) errcode |= PFERR_FETCH_MASK; walker->fault.vector = PF_VECTOR;

3 years, 2 months

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FAILED: patch "[PATCH] KVM: x86/mmu: Use MMU's role to detect CR4.SMEP value in" 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 ef318b9edf66a082f23d00d79b70c17b4c055a26 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Tue, 22 Jun 2021 10:56:49 -0700 Subject: [PATCH] KVM: x86/mmu: Use MMU's role to detect CR4.SMEP value in nested NPT walk Use the MMU's role to get its effective SMEP value when injecting a fault into the guest. When walking L1's (nested) NPT while L2 is active, vCPU state will reflect L2, whereas NPT uses the host's (L1 in this case) CR0, CR4, EFER, etc... If L1 and L2 have different settings for SMEP and L1 does not have EFER.NX=1, this can result in an incorrect PFEC.FETCH when injecting #NPF. Fixes: e57d4a356ad3 ("KVM: Add instruction fetch checking when walking guest page table") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210622175739.3610207-5-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 823a5919f9fa..52fffd68b522 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -471,8 +471,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, error: errcode |= write_fault | user_fault; - if (fetch_fault && (mmu->nx || - kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))) + if (fetch_fault && (mmu->nx || mmu->mmu_role.ext.cr4_smep)) errcode |= PFERR_FETCH_MASK; walker->fault.vector = PF_VECTOR;

3 years, 2 months

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FAILED: patch "[PATCH] KVM: x86/mmu: Use MMU's role to detect CR4.SMEP value in" 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 ef318b9edf66a082f23d00d79b70c17b4c055a26 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Tue, 22 Jun 2021 10:56:49 -0700 Subject: [PATCH] KVM: x86/mmu: Use MMU's role to detect CR4.SMEP value in nested NPT walk Use the MMU's role to get its effective SMEP value when injecting a fault into the guest. When walking L1's (nested) NPT while L2 is active, vCPU state will reflect L2, whereas NPT uses the host's (L1 in this case) CR0, CR4, EFER, etc... If L1 and L2 have different settings for SMEP and L1 does not have EFER.NX=1, this can result in an incorrect PFEC.FETCH when injecting #NPF. Fixes: e57d4a356ad3 ("KVM: Add instruction fetch checking when walking guest page table") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210622175739.3610207-5-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 823a5919f9fa..52fffd68b522 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -471,8 +471,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, error: errcode |= write_fault | user_fault; - if (fetch_fault && (mmu->nx || - kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))) + if (fetch_fault && (mmu->nx || mmu->mmu_role.ext.cr4_smep)) errcode |= PFERR_FETCH_MASK; walker->fault.vector = PF_VECTOR;

3 years, 2 months

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FAILED: patch "[PATCH] KVM: x86/mmu: Use MMU's role to detect CR4.SMEP value in" 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 ef318b9edf66a082f23d00d79b70c17b4c055a26 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Tue, 22 Jun 2021 10:56:49 -0700 Subject: [PATCH] KVM: x86/mmu: Use MMU's role to detect CR4.SMEP value in nested NPT walk Use the MMU's role to get its effective SMEP value when injecting a fault into the guest. When walking L1's (nested) NPT while L2 is active, vCPU state will reflect L2, whereas NPT uses the host's (L1 in this case) CR0, CR4, EFER, etc... If L1 and L2 have different settings for SMEP and L1 does not have EFER.NX=1, this can result in an incorrect PFEC.FETCH when injecting #NPF. Fixes: e57d4a356ad3 ("KVM: Add instruction fetch checking when walking guest page table") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210622175739.3610207-5-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 823a5919f9fa..52fffd68b522 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -471,8 +471,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, error: errcode |= write_fault | user_fault; - if (fetch_fault && (mmu->nx || - kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))) + if (fetch_fault && (mmu->nx || mmu->mmu_role.ext.cr4_smep)) errcode |= PFERR_FETCH_MASK; walker->fault.vector = PF_VECTOR;

3 years, 2 months

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FAILED: patch "[PATCH] KVM: x86/mmu: Use MMU's role to detect CR4.SMEP value in" 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 ef318b9edf66a082f23d00d79b70c17b4c055a26 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Tue, 22 Jun 2021 10:56:49 -0700 Subject: [PATCH] KVM: x86/mmu: Use MMU's role to detect CR4.SMEP value in nested NPT walk Use the MMU's role to get its effective SMEP value when injecting a fault into the guest. When walking L1's (nested) NPT while L2 is active, vCPU state will reflect L2, whereas NPT uses the host's (L1 in this case) CR0, CR4, EFER, etc... If L1 and L2 have different settings for SMEP and L1 does not have EFER.NX=1, this can result in an incorrect PFEC.FETCH when injecting #NPF. Fixes: e57d4a356ad3 ("KVM: Add instruction fetch checking when walking guest page table") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210622175739.3610207-5-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 823a5919f9fa..52fffd68b522 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -471,8 +471,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, error: errcode |= write_fault | user_fault; - if (fetch_fault && (mmu->nx || - kvm_read_cr4_bits(vcpu, X86_CR4_SMEP))) + if (fetch_fault && (mmu->nx || mmu->mmu_role.ext.cr4_smep)) errcode |= PFERR_FETCH_MASK; walker->fault.vector = PF_VECTOR;

3 years, 2 months

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FAILED: patch "[PATCH] KVM: x86/mmu: Treat NX as used (not reserved) for all !TDP" 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 112022bdb5bc372e00e6e43cb88ee38ea67b97bd Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc(a)google.com> Date: Tue, 22 Jun 2021 10:56:47 -0700 Subject: [PATCH] KVM: x86/mmu: Treat NX as used (not reserved) for all !TDP shadow MMUs Mark NX as being used for all non-nested shadow MMUs, as KVM will set the NX bit for huge SPTEs if the iTLB mutli-hit mitigation is enabled. Checking the mitigation itself is not sufficient as it can be toggled on at any time and KVM doesn't reset MMU contexts when that happens. KVM could reset the contexts, but that would require purging all SPTEs in all MMUs, for no real benefit. And, KVM already forces EFER.NX=1 when TDP is disabled (for WP=0, SMEP=1, NX=0), so technically NX is never reserved for shadow MMUs. Fixes: b8e8c8303ff2 ("kvm: mmu: ITLB_MULTIHIT mitigation") Cc: stable(a)vger.kernel.org Signed-off-by: Sean Christopherson <seanjc(a)google.com> Message-Id: <20210622175739.3610207-3-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 b3be690d081a..444e068e6ad9 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4221,7 +4221,15 @@ static inline u64 reserved_hpa_bits(void) void reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context) { - bool uses_nx = context->nx || + /* + * KVM uses NX when TDP is disabled to handle a variety of scenarios, + * notably for huge SPTEs if iTLB multi-hit mitigation is enabled and + * to generate correct permissions for CR0.WP=0/CR4.SMEP=1/EFER.NX=0. + * The iTLB multi-hit workaround can be toggled at any time, so assume + * NX can be used by any non-nested shadow MMU to avoid having to reset + * MMU contexts. Note, KVM forces EFER.NX=1 when TDP is disabled. + */ + bool uses_nx = context->nx || !tdp_enabled || context->mmu_role.base.smep_andnot_wp; struct rsvd_bits_validate *shadow_zero_check; int i;

3 years, 2 months

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FAILED: patch "[PATCH] KVM: PPC: Book3S HV: Save host FSCR in the P7/8 path" failed to apply to 5.13-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.13-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 6ba53317d497dec029bfb040b1daf38328fa00ab Mon Sep 17 00:00:00 2001 From: Nicholas Piggin <npiggin(a)gmail.com> Date: Wed, 26 May 2021 22:58:51 +1000 Subject: [PATCH] KVM: PPC: Book3S HV: Save host FSCR in the P7/8 path Similar to commit 25edcc50d76c ("KVM: PPC: Book3S HV: Save and restore FSCR in the P9 path"), ensure the P7/8 path saves and restores the host FSCR. The logic explained in that patch actually applies there to the old path well: a context switch can be made before kvmppc_vcpu_run_hv restores the host FSCR and returns. Now both the p9 and the p7/8 paths now save and restore their FSCR, it no longer needs to be restored at the end of kvmppc_vcpu_run_hv Fixes: b005255e12a3 ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs") Cc: stable(a)vger.kernel.org # v3.14+ Signed-off-by: Nicholas Piggin <npiggin(a)gmail.com> Reviewed-by: Fabiano Rosas <farosas(a)linux.ibm.com> Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au> Link: https://lore.kernel.org/r/20210526125851.3436735-1-npiggin@gmail.com diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 28a80d240b76..13728495ac66 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4455,7 +4455,6 @@ static int kvmppc_vcpu_run_hv(struct kvm_vcpu *vcpu) mtspr(SPRN_EBBRR, ebb_regs[1]); mtspr(SPRN_BESCR, ebb_regs[2]); mtspr(SPRN_TAR, user_tar); - mtspr(SPRN_FSCR, current->thread.fscr); } mtspr(SPRN_VRSAVE, user_vrsave); diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 5e634db4809b..004f0d4e665f 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -59,6 +59,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) #define STACK_SLOT_UAMOR (SFS-88) #define STACK_SLOT_DAWR1 (SFS-96) #define STACK_SLOT_DAWRX1 (SFS-104) +#define STACK_SLOT_FSCR (SFS-112) /* the following is used by the P9 short path */ #define STACK_SLOT_NVGPRS (SFS-152) /* 18 gprs */ @@ -686,6 +687,8 @@ BEGIN_FTR_SECTION std r6, STACK_SLOT_DAWR0(r1) std r7, STACK_SLOT_DAWRX0(r1) std r8, STACK_SLOT_IAMR(r1) + mfspr r5, SPRN_FSCR + std r5, STACK_SLOT_FSCR(r1) END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) BEGIN_FTR_SECTION mfspr r6, SPRN_DAWR1 @@ -1663,6 +1666,10 @@ FTR_SECTION_ELSE ld r7, STACK_SLOT_HFSCR(r1) mtspr SPRN_HFSCR, r7 ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300) +BEGIN_FTR_SECTION + ld r5, STACK_SLOT_FSCR(r1) + mtspr SPRN_FSCR, r5 +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) /* * Restore various registers to 0, where non-zero values * set by the guest could disrupt the host.

3 years, 2 months

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FAILED: patch "[PATCH] KVM: PPC: Book3S HV: Save host FSCR in the P7/8 path" failed to apply to 5.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.12-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 6ba53317d497dec029bfb040b1daf38328fa00ab Mon Sep 17 00:00:00 2001 From: Nicholas Piggin <npiggin(a)gmail.com> Date: Wed, 26 May 2021 22:58:51 +1000 Subject: [PATCH] KVM: PPC: Book3S HV: Save host FSCR in the P7/8 path Similar to commit 25edcc50d76c ("KVM: PPC: Book3S HV: Save and restore FSCR in the P9 path"), ensure the P7/8 path saves and restores the host FSCR. The logic explained in that patch actually applies there to the old path well: a context switch can be made before kvmppc_vcpu_run_hv restores the host FSCR and returns. Now both the p9 and the p7/8 paths now save and restore their FSCR, it no longer needs to be restored at the end of kvmppc_vcpu_run_hv Fixes: b005255e12a3 ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs") Cc: stable(a)vger.kernel.org # v3.14+ Signed-off-by: Nicholas Piggin <npiggin(a)gmail.com> Reviewed-by: Fabiano Rosas <farosas(a)linux.ibm.com> Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au> Link: https://lore.kernel.org/r/20210526125851.3436735-1-npiggin@gmail.com diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 28a80d240b76..13728495ac66 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4455,7 +4455,6 @@ static int kvmppc_vcpu_run_hv(struct kvm_vcpu *vcpu) mtspr(SPRN_EBBRR, ebb_regs[1]); mtspr(SPRN_BESCR, ebb_regs[2]); mtspr(SPRN_TAR, user_tar); - mtspr(SPRN_FSCR, current->thread.fscr); } mtspr(SPRN_VRSAVE, user_vrsave); diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 5e634db4809b..004f0d4e665f 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -59,6 +59,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) #define STACK_SLOT_UAMOR (SFS-88) #define STACK_SLOT_DAWR1 (SFS-96) #define STACK_SLOT_DAWRX1 (SFS-104) +#define STACK_SLOT_FSCR (SFS-112) /* the following is used by the P9 short path */ #define STACK_SLOT_NVGPRS (SFS-152) /* 18 gprs */ @@ -686,6 +687,8 @@ BEGIN_FTR_SECTION std r6, STACK_SLOT_DAWR0(r1) std r7, STACK_SLOT_DAWRX0(r1) std r8, STACK_SLOT_IAMR(r1) + mfspr r5, SPRN_FSCR + std r5, STACK_SLOT_FSCR(r1) END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) BEGIN_FTR_SECTION mfspr r6, SPRN_DAWR1 @@ -1663,6 +1666,10 @@ FTR_SECTION_ELSE ld r7, STACK_SLOT_HFSCR(r1) mtspr SPRN_HFSCR, r7 ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300) +BEGIN_FTR_SECTION + ld r5, STACK_SLOT_FSCR(r1) + mtspr SPRN_FSCR, r5 +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) /* * Restore various registers to 0, where non-zero values * set by the guest could disrupt the host.

3 years, 2 months

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Linux-stable-mirror July 2021