From e2dec939db126989808853d218e426daaeebc9e2 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Fri, 5 Jan 2007 16:36:54 -0800 Subject: [PATCH] [PATCH] KVM: MMU: Detect oom conditions and propagate error to userspace Signed-off-by: Avi Kivity Acked-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/kvm/mmu.c | 32 +++++++++++++++++++++----------- drivers/kvm/paging_tmpl.h | 8 ++++++-- drivers/kvm/svm.c | 14 +++++++++++--- drivers/kvm/vmx.c | 15 ++++++++++++--- 4 files changed, 50 insertions(+), 19 deletions(-) diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c index e96362aa7947..7761089ef3bc 100644 --- a/drivers/kvm/mmu.c +++ b/drivers/kvm/mmu.c @@ -166,19 +166,20 @@ static int is_rmap_pte(u64 pte) == (PT_WRITABLE_MASK | PT_PRESENT_MASK); } -static void mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, - size_t objsize, int min) +static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, + size_t objsize, int min) { void *obj; if (cache->nobjs >= min) - return; + return 0; while (cache->nobjs < ARRAY_SIZE(cache->objects)) { obj = kzalloc(objsize, GFP_NOWAIT); if (!obj) - BUG(); + return -ENOMEM; cache->objects[cache->nobjs++] = obj; } + return 0; } static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc) @@ -187,12 +188,18 @@ static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc) kfree(mc->objects[--mc->nobjs]); } -static void mmu_topup_memory_caches(struct kvm_vcpu *vcpu) +static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu) { - mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache, - sizeof(struct kvm_pte_chain), 4); - mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache, - sizeof(struct kvm_rmap_desc), 1); + int r; + + r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache, + sizeof(struct kvm_pte_chain), 4); + if (r) + goto out; + r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache, + sizeof(struct kvm_rmap_desc), 1); +out: + return r; } static void mmu_free_memory_caches(struct kvm_vcpu *vcpu) @@ -824,8 +831,11 @@ static int nonpaging_page_fault(struct kvm_vcpu *vcpu, gva_t gva, { gpa_t addr = gva; hpa_t paddr; + int r; - mmu_topup_memory_caches(vcpu); + r = mmu_topup_memory_caches(vcpu); + if (r) + return r; ASSERT(vcpu); ASSERT(VALID_PAGE(vcpu->mmu.root_hpa)); @@ -1052,7 +1062,7 @@ int kvm_mmu_reset_context(struct kvm_vcpu *vcpu) r = init_kvm_mmu(vcpu); if (r < 0) goto out; - mmu_topup_memory_caches(vcpu); + r = mmu_topup_memory_caches(vcpu); out: return r; } diff --git a/drivers/kvm/paging_tmpl.h b/drivers/kvm/paging_tmpl.h index 4e6670ff1847..32b385188454 100644 --- a/drivers/kvm/paging_tmpl.h +++ b/drivers/kvm/paging_tmpl.h @@ -339,7 +339,8 @@ static int FNAME(fix_write_pf)(struct kvm_vcpu *vcpu, * - normal guest page fault due to the guest pte marked not present, not * writable, or not executable * - * Returns: 1 if we need to emulate the instruction, 0 otherwise + * Returns: 1 if we need to emulate the instruction, 0 otherwise, or + * a negative value on error. */ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u32 error_code) @@ -351,10 +352,13 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr, u64 *shadow_pte; int fixed; int write_pt = 0; + int r; pgprintk("%s: addr %lx err %x\n", __FUNCTION__, addr, error_code); - mmu_topup_memory_caches(vcpu); + r = mmu_topup_memory_caches(vcpu); + if (r) + return r; /* * Look up the shadow pte for the faulting address. diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c index 99250011a471..af1e7b3f9171 100644 --- a/drivers/kvm/svm.c +++ b/drivers/kvm/svm.c @@ -852,6 +852,7 @@ static int pf_interception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) u64 fault_address; u32 error_code; enum emulation_result er; + int r; if (is_external_interrupt(exit_int_info)) push_irq(vcpu, exit_int_info & SVM_EVTINJ_VEC_MASK); @@ -860,7 +861,12 @@ static int pf_interception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) fault_address = vcpu->svm->vmcb->control.exit_info_2; error_code = vcpu->svm->vmcb->control.exit_info_1; - if (!kvm_mmu_page_fault(vcpu, fault_address, error_code)) { + r = kvm_mmu_page_fault(vcpu, fault_address, error_code); + if (r < 0) { + spin_unlock(&vcpu->kvm->lock); + return r; + } + if (!r) { spin_unlock(&vcpu->kvm->lock); return 1; } @@ -1398,6 +1404,7 @@ static int svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) u16 fs_selector; u16 gs_selector; u16 ldt_selector; + int r; again: do_interrupt_requests(vcpu, kvm_run); @@ -1565,7 +1572,8 @@ again: return 0; } - if (handle_exit(vcpu, kvm_run)) { + r = handle_exit(vcpu, kvm_run); + if (r > 0) { if (signal_pending(current)) { ++kvm_stat.signal_exits; post_kvm_run_save(vcpu, kvm_run); @@ -1581,7 +1589,7 @@ again: goto again; } post_kvm_run_save(vcpu, kvm_run); - return 0; + return r; } static void svm_flush_tlb(struct kvm_vcpu *vcpu) diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c index 59178ad4d344..ed3956739771 100644 --- a/drivers/kvm/vmx.c +++ b/drivers/kvm/vmx.c @@ -1289,6 +1289,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) unsigned long cr2, rip; u32 vect_info; enum emulation_result er; + int r; vect_info = vmcs_read32(IDT_VECTORING_INFO_FIELD); intr_info = vmcs_read32(VM_EXIT_INTR_INFO); @@ -1317,7 +1318,12 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) cr2 = vmcs_readl(EXIT_QUALIFICATION); spin_lock(&vcpu->kvm->lock); - if (!kvm_mmu_page_fault(vcpu, cr2, error_code)) { + r = kvm_mmu_page_fault(vcpu, cr2, error_code); + if (r < 0) { + spin_unlock(&vcpu->kvm->lock); + return r; + } + if (!r) { spin_unlock(&vcpu->kvm->lock); return 1; } @@ -1680,6 +1686,7 @@ static int vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) u8 fail; u16 fs_sel, gs_sel, ldt_sel; int fs_gs_ldt_reload_needed; + int r; again: /* @@ -1853,6 +1860,7 @@ again: if (fail) { kvm_run->exit_type = KVM_EXIT_TYPE_FAIL_ENTRY; kvm_run->exit_reason = vmcs_read32(VM_INSTRUCTION_ERROR); + r = 0; } else { if (fs_gs_ldt_reload_needed) { load_ldt(ldt_sel); @@ -1872,7 +1880,8 @@ again: } vcpu->launched = 1; kvm_run->exit_type = KVM_EXIT_TYPE_VM_EXIT; - if (kvm_handle_exit(kvm_run, vcpu)) { + r = kvm_handle_exit(kvm_run, vcpu); + if (r > 0) { /* Give scheduler a change to reschedule. */ if (signal_pending(current)) { ++kvm_stat.signal_exits; @@ -1892,7 +1901,7 @@ again: } post_kvm_run_save(vcpu, kvm_run); - return 0; + return r; } static void vmx_flush_tlb(struct kvm_vcpu *vcpu)