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| author | Bandan Das <bsd@redhat.com> | 2016-07-12 18:18:49 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2016-07-14 09:03:14 +0200 |
| commit | ffb128c89b77b44da18ccf51844a8e750e2c427a (patch) | |
| tree | 2343268f9b507a99abf34bf20d99b1158488b67e /arch/x86/kvm/mmu.c | |
| parent | 812f30b234539ccb0139f92dfdbec1e8158cf535 (diff) | |
| download | lwn-ffb128c89b77b44da18ccf51844a8e750e2c427a.tar.gz lwn-ffb128c89b77b44da18ccf51844a8e750e2c427a.zip | |
kvm: mmu: don't set the present bit unconditionally
To support execute only mappings on behalf of L1
hypervisors, we need to teach set_spte() to honor all three of
L1's XWR bits. As a start, add a new variable "shadow_present_mask"
that will be set for non-EPT shadow paging and clear for EPT.
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 6471f8788bd2..b8628e905806 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -175,6 +175,7 @@ static u64 __read_mostly shadow_user_mask; static u64 __read_mostly shadow_accessed_mask; static u64 __read_mostly shadow_dirty_mask; static u64 __read_mostly shadow_mmio_mask; +static u64 __read_mostly shadow_present_mask; static void mmu_spte_set(u64 *sptep, u64 spte); static void mmu_free_roots(struct kvm_vcpu *vcpu); @@ -282,13 +283,14 @@ static bool check_mmio_spte(struct kvm_vcpu *vcpu, u64 spte) } void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask, - u64 dirty_mask, u64 nx_mask, u64 x_mask) + u64 dirty_mask, u64 nx_mask, u64 x_mask, u64 p_mask) { shadow_user_mask = user_mask; shadow_accessed_mask = accessed_mask; shadow_dirty_mask = dirty_mask; shadow_nx_mask = nx_mask; shadow_x_mask = x_mask; + shadow_present_mask = p_mask; } EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes); @@ -2245,10 +2247,9 @@ static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep, { u64 spte; - BUILD_BUG_ON(VMX_EPT_READABLE_MASK != PT_PRESENT_MASK || - VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK); + BUILD_BUG_ON(VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK); - spte = __pa(sp->spt) | PT_PRESENT_MASK | PT_WRITABLE_MASK | + spte = __pa(sp->spt) | shadow_present_mask | PT_WRITABLE_MASK | shadow_user_mask | shadow_x_mask | shadow_accessed_mask; mmu_spte_set(sptep, spte); @@ -2515,13 +2516,13 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn, kvm_pfn_t pfn, bool speculative, bool can_unsync, bool host_writable) { - u64 spte; + u64 spte = 0; int ret = 0; if (set_mmio_spte(vcpu, sptep, gfn, pfn, pte_access)) return 0; - spte = PT_PRESENT_MASK; + spte |= shadow_present_mask; if (!speculative) spte |= shadow_accessed_mask; |