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| author |   Sean Christopherson <sean.j.christopherson@intel.com> | 2019-06-13 10:22:23 -0700 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2019-06-19 16:11:53 +0200 |
| commit | b6b80c78af838bef17501416d5d383fedab0010a (patch) | |
| tree | 76b590a99b933501b98e51585cf6f2d42fc3c8d1 /arch | |
| parent | KVM: x86: Modify struct kvm_nested_state to have explicit fields for data (diff) | |
| download | linux-dev-b6b80c78af838bef17501416d5d383fedab0010a.tar.xz linux-dev-b6b80c78af838bef17501416d5d383fedab0010a.zip | |
KVM: x86/mmu: Allocate PAE root array when using SVM's 32-bit NPT
SVM's Nested Page Tables (NPT) reuses x86 paging for the host-controlled
page walk. For 32-bit KVM, this means PAE paging is used even when TDP
is enabled, i.e. the PAE root array needs to be allocated.
Fixes: ee6268ba3a68 ("KVM: x86: Skip pae_root shadow allocation if tdp enabled")
Cc: stable@vger.kernel.org
Reported-by: Jiri Palecek <jpalecek@web.de>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 1e9ba81accba..d3c3d5e5ffd4 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -5602,14 +5602,18 @@ static int alloc_mmu_pages(struct kvm_vcpu *vcpu) struct page *page; int i; - if (tdp_enabled) - return 0; - /* - * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64. - * Therefore we need to allocate shadow page tables in the first - * 4GB of memory, which happens to fit the DMA32 zone. + * When using PAE paging, the four PDPTEs are treated as 'root' pages, + * 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. */ + if (tdp_enabled && kvm_x86_ops->get_tdp_level(vcpu) > PT32E_ROOT_LEVEL) + return 0; + page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_DMA32); if (!page) return -ENOMEM; |