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| author | Avi Kivity <avi@qumranet.com> | 2007-12-30 12:29:05 +0200 |
|---|---|---|
| committer | Avi Kivity <avi@qumranet.com> | 2008-01-30 18:01:21 +0200 |
| commit | d7824fff896a1698a07a8046dc362f4500c302f7 (patch) | |
| tree | 249e23ec224bc621bea1ef24fa83f5a749d6b35b /arch/x86/kvm/paging_tmpl.h | |
| parent | 7ec54588210df29ea637e6054489bc942c0ef371 (diff) | |
| download | blackbird-op-linux-d7824fff896a1698a07a8046dc362f4500c302f7.tar.gz blackbird-op-linux-d7824fff896a1698a07a8046dc362f4500c302f7.zip | |
KVM: MMU: Avoid calling gfn_to_page() in mmu_set_spte()
Since gfn_to_page() is a sleeping function, and we want to make the core mmu
spinlocked, we need to pass the page from the walker context (which can sleep)
to the shadow context (which cannot).
[marcelo: avoid recursive locking of mmap_sem]
Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'arch/x86/kvm/paging_tmpl.h')
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 136a65d72b0a..3d7846ba26e1 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -245,6 +245,7 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page, { pt_element_t gpte; unsigned pte_access; + struct page *npage; gpte = *(const pt_element_t *)pte; if (~gpte & (PT_PRESENT_MASK | PT_ACCESSED_MASK)) { @@ -256,8 +257,14 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page, return; pgprintk("%s: gpte %llx spte %p\n", __FUNCTION__, (u64)gpte, spte); pte_access = page->role.access & FNAME(gpte_access)(vcpu, gpte); + if (gpte_to_gfn(gpte) != vcpu->arch.update_pte.gfn) + return; + npage = vcpu->arch.update_pte.page; + if (!npage) + return; + get_page(npage); mmu_set_spte(vcpu, spte, page->role.access, pte_access, 0, 0, - gpte & PT_DIRTY_MASK, NULL, gpte_to_gfn(gpte)); + gpte & PT_DIRTY_MASK, NULL, gpte_to_gfn(gpte), npage); } /* @@ -265,7 +272,8 @@ static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *page, */ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, struct guest_walker *walker, - int user_fault, int write_fault, int *ptwrite) + int user_fault, int write_fault, int *ptwrite, + struct page *page) { hpa_t shadow_addr; int level; @@ -321,8 +329,10 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, r = kvm_read_guest_atomic(vcpu->kvm, walker->pte_gpa[level - 2], &curr_pte, sizeof(curr_pte)); - if (r || curr_pte != walker->ptes[level - 2]) + if (r || curr_pte != walker->ptes[level - 2]) { + kvm_release_page_clean(page); return NULL; + } } shadow_addr = __pa(shadow_page->spt); shadow_pte = shadow_addr | PT_PRESENT_MASK | PT_ACCESSED_MASK @@ -333,7 +343,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, mmu_set_spte(vcpu, shadow_ent, access, walker->pte_access & access, user_fault, write_fault, walker->ptes[walker->level-1] & PT_DIRTY_MASK, - ptwrite, walker->gfn); + ptwrite, walker->gfn, page); return shadow_ent; } @@ -362,6 +372,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u64 *shadow_pte; int write_pt = 0; int r; + struct page *page; pgprintk("%s: addr %lx err %x\n", __FUNCTION__, addr, error_code); kvm_mmu_audit(vcpu, "pre page fault"); @@ -388,9 +399,11 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, return 0; } + page = gfn_to_page(vcpu->kvm, walker.gfn); + mutex_lock(&vcpu->kvm->lock); shadow_pte = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault, - &write_pt); + &write_pt, page); pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __FUNCTION__, shadow_pte, *shadow_pte, write_pt); |
