From 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 Mon Sep 17 00:00:00 2001 From: Marcelo Tosatti Date: Fri, 22 Oct 2010 14:18:18 -0200 Subject: KVM: propagate fault r/w information to gup(), allow read-only memory As suggested by Andrea, pass r/w error code to gup(), upgrading read fault to writable if host pte allows it. Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity --- arch/x86/kvm/paging_tmpl.h | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'arch/x86/kvm/paging_tmpl.h') diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index d6b281e989b1..ba00eefa7bcd 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -427,7 +427,7 @@ static void FNAME(pte_prefetch)(struct kvm_vcpu *vcpu, struct guest_walker *gw, static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, struct guest_walker *gw, int user_fault, int write_fault, int hlevel, - int *ptwrite, pfn_t pfn) + int *ptwrite, pfn_t pfn, bool map_writable) { unsigned access = gw->pt_access; struct kvm_mmu_page *sp = NULL; @@ -501,7 +501,7 @@ static u64 *FNAME(fetch)(struct kvm_vcpu *vcpu, gva_t addr, mmu_set_spte(vcpu, it.sptep, access, gw->pte_access & access, user_fault, write_fault, dirty, ptwrite, it.level, - gw->gfn, pfn, false, true); + gw->gfn, pfn, false, map_writable); FNAME(pte_prefetch)(vcpu, gw, it.sptep); return it.sptep; @@ -539,6 +539,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code, pfn_t pfn; int level = PT_PAGE_TABLE_LEVEL; unsigned long mmu_seq; + bool map_writable; pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code); @@ -569,13 +570,17 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code, mmu_seq = vcpu->kvm->mmu_notifier_seq; smp_rmb(); - if (try_async_pf(vcpu, no_apf, walker.gfn, addr, &pfn)) + if (try_async_pf(vcpu, no_apf, walker.gfn, addr, &pfn, write_fault, + &map_writable)) return 0; /* mmio */ if (is_error_pfn(pfn)) return kvm_handle_bad_page(vcpu->kvm, walker.gfn, pfn); + if (!map_writable) + walker.pte_access &= ~ACC_WRITE_MASK; + spin_lock(&vcpu->kvm->mmu_lock); if (mmu_notifier_retry(vcpu, mmu_seq)) goto out_unlock; @@ -583,7 +588,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code, trace_kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT); kvm_mmu_free_some_pages(vcpu); sptep = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault, - level, &write_pt, pfn); + level, &write_pt, pfn, map_writable); (void)sptep; pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __func__, sptep, *sptep, write_pt); -- cgit v1.2.1