diff options
| author | Jiří Paleček <jpalecek@web.de> | 2019-06-22 19:42:04 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-05 15:12:12 +0200 |
| commit | dfe00eddab37232b614fc4bf790125f3551867de (patch) | |
| tree | 78f5704ab041a484166241c76407a83e1b673aef | |
| parent | b01d7910727edb3a116d182151a319e453082a11 (diff) | |
kvm: Nested KVM MMUs need PAE root too
[ Upstream commit 1cfff4d9a5d01fa61e5768a6afffc81ae1c8ecb9 ]
On AMD processors, in PAE 32bit mode, nested KVM instances don't
work. The L0 host get a kernel OOPS, which is related to
arch.mmu->pae_root being NULL.
The reason for this is that when setting up nested KVM instance,
arch.mmu is set to &arch.guest_mmu (while normally, it would be
&arch.root_mmu). However, the initialization and allocation of
pae_root only creates it in root_mmu. KVM code (ie. in
mmu_alloc_shadow_roots) then accesses arch.mmu->pae_root, which is the
unallocated arch.guest_mmu->pae_root.
This fix just allocates (and frees) pae_root in both guest_mmu and
root_mmu (and also lm_root if it was allocated). The allocation is
subject to previous restrictions ie. it won't allocate anything on
64-bit and AFAIK not on Intel.
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=203923
Fixes: 14c07ad89f4d ("x86/kvm/mmu: introduce guest_mmu")
Signed-off-by: Jiri Palecek <jpalecek@web.de>
Tested-by: Jiri Palecek <jpalecek@web.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/x86/kvm/mmu.c | 30 |
1 files changed, 22 insertions, 8 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index a63964e7cec7..c68bf3aab12c 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -5611,13 +5611,13 @@ slot_handle_leaf(struct kvm *kvm, struct kvm_memory_slot *memslot, PT_PAGE_TABLE_LEVEL, lock_flush_tlb); } -static void free_mmu_pages(struct kvm_vcpu *vcpu) +static void free_mmu_pages(struct kvm_mmu *mmu) { - free_page((unsigned long)vcpu->arch.mmu->pae_root); - free_page((unsigned long)vcpu->arch.mmu->lm_root); + free_page((unsigned long)mmu->pae_root); + free_page((unsigned long)mmu->lm_root); } -static int alloc_mmu_pages(struct kvm_vcpu *vcpu) +static int alloc_mmu_pages(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu) { struct page *page; int i; @@ -5638,9 +5638,9 @@ static int alloc_mmu_pages(struct kvm_vcpu *vcpu) if (!page) return -ENOMEM; - vcpu->arch.mmu->pae_root = page_address(page); + mmu->pae_root = page_address(page); for (i = 0; i < 4; ++i) - vcpu->arch.mmu->pae_root[i] = INVALID_PAGE; + mmu->pae_root[i] = INVALID_PAGE; return 0; } @@ -5648,6 +5648,7 @@ static int alloc_mmu_pages(struct kvm_vcpu *vcpu) int kvm_mmu_create(struct kvm_vcpu *vcpu) { uint i; + int ret; vcpu->arch.mmu = &vcpu->arch.root_mmu; vcpu->arch.walk_mmu = &vcpu->arch.root_mmu; @@ -5665,7 +5666,19 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu) vcpu->arch.guest_mmu.prev_roots[i] = KVM_MMU_ROOT_INFO_INVALID; vcpu->arch.nested_mmu.translate_gpa = translate_nested_gpa; - return alloc_mmu_pages(vcpu); + + ret = alloc_mmu_pages(vcpu, &vcpu->arch.guest_mmu); + if (ret) + return ret; + + ret = alloc_mmu_pages(vcpu, &vcpu->arch.root_mmu); + if (ret) + goto fail_allocate_root; + + return ret; + fail_allocate_root: + free_mmu_pages(&vcpu->arch.guest_mmu); + return ret; } @@ -6168,7 +6181,8 @@ unsigned long kvm_mmu_calculate_default_mmu_pages(struct kvm *kvm) void kvm_mmu_destroy(struct kvm_vcpu *vcpu) { kvm_mmu_unload(vcpu); - free_mmu_pages(vcpu); + free_mmu_pages(&vcpu->arch.root_mmu); + free_mmu_pages(&vcpu->arch.guest_mmu); mmu_free_memory_caches(vcpu); } |