From: Greg Kroah-Hartman Date: Mon, 5 Jul 2021 10:39:28 +0000 (+0200) Subject: 5.12-stable patches X-Git-Tag: v5.13.1~2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=01b83f4a1248da48d92f76f6d5f920480a2b9a11;p=thirdparty%2Fkernel%2Fstable-queue.git 5.12-stable patches added patches: revert-kvm-x86-mmu-drop-kvm_mmu_extended_role.cr4_la57-hack.patch --- diff --git a/queue-5.12/revert-kvm-x86-mmu-drop-kvm_mmu_extended_role.cr4_la57-hack.patch b/queue-5.12/revert-kvm-x86-mmu-drop-kvm_mmu_extended_role.cr4_la57-hack.patch new file mode 100644 index 00000000000..cb8d8222456 --- /dev/null +++ b/queue-5.12/revert-kvm-x86-mmu-drop-kvm_mmu_extended_role.cr4_la57-hack.patch @@ -0,0 +1,62 @@ +From f71a53d1180d5ecc346f0c6a23191d837fe2871b Mon Sep 17 00:00:00 2001 +From: Sean Christopherson +Date: Tue, 22 Jun 2021 10:56:50 -0700 +Subject: Revert "KVM: x86/mmu: Drop kvm_mmu_extended_role.cr4_la57 hack" + +From: Sean Christopherson + +commit f71a53d1180d5ecc346f0c6a23191d837fe2871b upstream. + +Restore CR4.LA57 to the mmu_role to fix an amusing edge case with nested +virtualization. When KVM (L0) is using TDP, CR4.LA57 is not reflected in +mmu_role.base.level because that tracks the shadow root level, i.e. TDP +level. Normally, this is not an issue because LA57 can't be toggled +while long mode is active, i.e. the guest has to first disable paging, +then toggle LA57, then re-enable paging, thus ensuring an MMU +reinitialization. + +But if L1 is crafty, it can load a new CR4 on VM-Exit and toggle LA57 +without having to bounce through an unpaged section. L1 can also load a +new CR3 on exit, i.e. it doesn't even need to play crazy paging games, a +single entry PML5 is sufficient. Such shenanigans are only problematic +if L0 and L1 use TDP, otherwise L1 and L2 share an MMU that gets +reinitialized on nested VM-Enter/VM-Exit due to mmu_role.base.guest_mode. + +Note, in the L2 case with nested TDP, even though L1 can switch between +L2s with different LA57 settings, thus bypassing the paging requirement, +in that case KVM's nested_mmu will track LA57 in base.level. + +This reverts commit 8053f924cad30bf9f9a24e02b6c8ddfabf5202ea. + +Fixes: 8053f924cad3 ("KVM: x86/mmu: Drop kvm_mmu_extended_role.cr4_la57 hack") +Cc: stable@vger.kernel.org +Signed-off-by: Sean Christopherson +Message-Id: <20210622175739.3610207-6-seanjc@google.com> +Signed-off-by: Paolo Bonzini +Signed-off-by: Greg Kroah-Hartman + +--- + arch/x86/include/asm/kvm_host.h | 1 + + arch/x86/kvm/mmu/mmu.c | 1 + + 2 files changed, 2 insertions(+) + +--- a/arch/x86/include/asm/kvm_host.h ++++ b/arch/x86/include/asm/kvm_host.h +@@ -307,6 +307,7 @@ union kvm_mmu_extended_role { + unsigned int cr4_pke:1; + unsigned int cr4_smap:1; + unsigned int cr4_smep:1; ++ unsigned int cr4_la57:1; + unsigned int maxphyaddr:6; + }; + }; +--- a/arch/x86/kvm/mmu/mmu.c ++++ b/arch/x86/kvm/mmu/mmu.c +@@ -4463,6 +4463,7 @@ static union kvm_mmu_extended_role kvm_c + ext.cr4_smap = !!kvm_read_cr4_bits(vcpu, X86_CR4_SMAP); + ext.cr4_pse = !!is_pse(vcpu); + ext.cr4_pke = !!kvm_read_cr4_bits(vcpu, X86_CR4_PKE); ++ ext.cr4_la57 = !!kvm_read_cr4_bits(vcpu, X86_CR4_LA57); + ext.maxphyaddr = cpuid_maxphyaddr(vcpu); + + ext.valid = 1; diff --git a/queue-5.12/series b/queue-5.12/series index 7058b8f1c8b..f3e645b69c3 100644 --- a/queue-5.12/series +++ b/queue-5.12/series @@ -3,3 +3,4 @@ s390-vfio-ap-clean-up-mdev-resources-when-remove-cal.patch gpio-mxc-fix-disabled-interrupt-wake-up-support.patch drm-nouveau-fix-dma_address-check-for-cpu-gpu-sync.patch gpio-amd8111-and-tqmx86-require-has_ioport_map.patch +revert-kvm-x86-mmu-drop-kvm_mmu_extended_role.cr4_la57-hack.patch