5.11-stable patches

added patches:
	revert-kvm-x86-mmu-drop-kvm_mmu_extended_role.cr4_la57-hack.patch

diff --git a/queue-5.11/revert-kvm-x86-mmu-drop-kvm_mmu_extended_role.cr4_la57-hack.patch b/queue-5.11/revert-kvm-x86-mmu-drop-kvm_mmu_extended_role.cr4_la57-hack.patch
new file mode 100644 (file)
index 0000000..cb8d822
--- /dev/null
+++ b/queue-5.11/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 <seanjc@google.com>
+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 <seanjc@google.com>
+
+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 <seanjc@google.com>
+Message-Id: <20210622175739.3610207-6-seanjc@google.com>
+Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ 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;