diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c index c6f972914f082e9af20ca6af54d155104ef5d2ba..a05d0609d918b17d543438bf4423cabf24ddccb6 100644 --- a/drivers/kvm/mmu.c +++ b/drivers/kvm/mmu.c @@ -992,16 +992,6 @@ static inline int fix_read_pf(u64 *shadow_ent) return 0; } -static int may_access(u64 pte, int write, int user) -{ - - if (user && !(pte & PT_USER_MASK)) - return 0; - if (write && !(pte & PT_WRITABLE_MASK)) - return 0; - return 1; -} - static void paging_free(struct kvm_vcpu *vcpu) { nonpaging_free(vcpu); diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h index 6bc41950fbb352a96b86af4d0196822248c9b218..afcd2a8f45bbc5d42c2fb97ca0dacae45a9abe59 100644 --- a/drivers/kvm/paging_tmpl.h +++ b/drivers/kvm/paging_tmpl.h @@ -63,13 +63,15 @@ struct guest_walker { pt_element_t *ptep; pt_element_t inherited_ar; gfn_t gfn; + u32 error_code; }; /* * Fetch a guest pte for a guest virtual address */ -static void FNAME(walk_addr)(struct guest_walker *walker, - struct kvm_vcpu *vcpu, gva_t addr) +static int FNAME(walk_addr)(struct guest_walker *walker, + struct kvm_vcpu *vcpu, gva_t addr, + int write_fault, int user_fault) { hpa_t hpa; struct kvm_memory_slot *slot; @@ -86,7 +88,7 @@ static void FNAME(walk_addr)(struct guest_walker *walker, walker->ptep = &vcpu->pdptrs[(addr >> 30) & 3]; root = *walker->ptep; if (!(root & PT_PRESENT_MASK)) - return; + goto not_present; --walker->level; } #endif @@ -111,11 +113,18 @@ static void FNAME(walk_addr)(struct guest_walker *walker, ASSERT(((unsigned long)walker->table & PAGE_MASK) == ((unsigned long)ptep & PAGE_MASK)); - if (is_present_pte(*ptep) && !(*ptep & PT_ACCESSED_MASK)) - *ptep |= PT_ACCESSED_MASK; - if (!is_present_pte(*ptep)) - break; + goto not_present; + + if (write_fault && !is_writeble_pte(*ptep)) + if (user_fault || is_write_protection(vcpu)) + goto access_error; + + if (user_fault && !(*ptep & PT_USER_MASK)) + goto access_error; + + if (!(*ptep & PT_ACCESSED_MASK)) + *ptep |= PT_ACCESSED_MASK; /* avoid rmw */ if (walker->level == PT_PAGE_TABLE_LEVEL) { walker->gfn = (*ptep & PT_BASE_ADDR_MASK) @@ -146,6 +155,21 @@ static void FNAME(walk_addr)(struct guest_walker *walker, } walker->ptep = ptep; pgprintk("%s: pte %llx\n", __FUNCTION__, (u64)*ptep); + return 1; + +not_present: + walker->error_code = 0; + goto err; + +access_error: + walker->error_code = PFERR_PRESENT_MASK; + +err: + if (write_fault) + walker->error_code |= PFERR_WRITE_MASK; + if (user_fault) + walker->error_code |= PFERR_USER_MASK; + return 0; } static void FNAME(release_walker)(struct guest_walker *walker) @@ -347,7 +371,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code) { int write_fault = error_code & PFERR_WRITE_MASK; - int pte_present = error_code & PFERR_PRESENT_MASK; int user_fault = error_code & PFERR_USER_MASK; struct guest_walker walker; u64 *shadow_pte; @@ -365,19 +388,19 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, /* * Look up the shadow pte for the faulting address. */ - FNAME(walk_addr)(&walker, vcpu, addr); - shadow_pte = FNAME(fetch)(vcpu, addr, &walker); + r = FNAME(walk_addr)(&walker, vcpu, addr, write_fault, user_fault); /* * The page is not mapped by the guest. Let the guest handle it. */ - if (!shadow_pte) { - pgprintk("%s: not mapped\n", __FUNCTION__); - inject_page_fault(vcpu, addr, error_code); + if (!r) { + pgprintk("%s: guest page fault\n", __FUNCTION__); + inject_page_fault(vcpu, addr, walker.error_code); FNAME(release_walker)(&walker); return 0; } + shadow_pte = FNAME(fetch)(vcpu, addr, &walker); pgprintk("%s: shadow pte %p %llx\n", __FUNCTION__, shadow_pte, *shadow_pte); @@ -399,22 +422,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, * mmio: emulate if accessible, otherwise its a guest fault. */ if (is_io_pte(*shadow_pte)) { - if (may_access(*shadow_pte, write_fault, user_fault)) - return 1; - pgprintk("%s: io work, no access\n", __FUNCTION__); - inject_page_fault(vcpu, addr, - error_code | PFERR_PRESENT_MASK); - kvm_mmu_audit(vcpu, "post page fault (io)"); - return 0; - } - - /* - * pte not present, guest page fault. - */ - if (pte_present && !fixed && !write_pt) { - inject_page_fault(vcpu, addr, error_code); - kvm_mmu_audit(vcpu, "post page fault (guest)"); - return 0; + return 1; } ++kvm_stat.pf_fixed; @@ -429,7 +437,7 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t vaddr) pt_element_t guest_pte; gpa_t gpa; - FNAME(walk_addr)(&walker, vcpu, vaddr); + FNAME(walk_addr)(&walker, vcpu, vaddr, 0, 0); guest_pte = *walker.ptep; FNAME(release_walker)(&walker);