KVM: MMU: Track page fault data in struct vcpu

This patch introduces a struct with two new fields in
vcpu_arch for x86:

	* fault.address
	* fault.error_code

This will be used to correctly propagate page faults back
into the guest when we could have either an ordinary page
fault or a nested page fault. In the case of a nested page
fault the fault-address is different from the original
address that should be walked. So we need to keep track
about the real fault-address.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 1bf1140..5187dd8 100644 (file)
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -229,7 +229,6 @@ struct x86_emulate_ctxt {
        int exception; /* exception that happens during emulation or -1 */
        u32 error_code; /* error code for exception */
        bool error_code_valid;
-       unsigned long cr2; /* faulted address in case of #PF */
 
        /* decode cache */
        struct decode_cache decode;

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 009a4a1..3fde5b3 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -239,9 +239,7 @@ struct kvm_mmu {
        void (*set_cr3)(struct kvm_vcpu *vcpu, unsigned long root);
        unsigned long (*get_cr3)(struct kvm_vcpu *vcpu);
        int (*page_fault)(struct kvm_vcpu *vcpu, gva_t gva, u32 err);
-       void (*inject_page_fault)(struct kvm_vcpu *vcpu,
-                                 unsigned long addr,
-                                 u32 error_code);
+       void (*inject_page_fault)(struct kvm_vcpu *vcpu);
        void (*free)(struct kvm_vcpu *vcpu);
        gpa_t (*gva_to_gpa)(struct kvm_vcpu *vcpu, gva_t gva, u32 access,
                            u32 *error);
@@ -288,6 +286,16 @@ struct kvm_vcpu_arch {
        bool tpr_access_reporting;
 
        struct kvm_mmu mmu;
+
+       /*
+        * This struct is filled with the necessary information to propagate a
+        * page fault into the guest
+        */
+       struct {
+               u64      address;
+               unsigned error_code;
+       } fault;
+
        /* only needed in kvm_pv_mmu_op() path, but it's hot so
         * put it here to avoid allocation */
        struct kvm_pv_mmu_op_buffer mmu_op_buffer;
@@ -624,8 +632,7 @@ void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr);
 void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code);
 void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr);
 void kvm_requeue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code);
-void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long cr2,
-                          u32 error_code);
+void kvm_inject_page_fault(struct kvm_vcpu *vcpu);
 bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl);
 
 int kvm_pic_set_irq(void *opaque, int irq, int level);

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 27d2c22..2b08b78 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -487,11 +487,9 @@ static void emulate_gp(struct x86_emulate_ctxt *ctxt, int err)
        emulate_exception(ctxt, GP_VECTOR, err, true);
 }
 
-static void emulate_pf(struct x86_emulate_ctxt *ctxt, unsigned long addr,
-                      int err)
+static void emulate_pf(struct x86_emulate_ctxt *ctxt)
 {
-       ctxt->cr2 = addr;
-       emulate_exception(ctxt, PF_VECTOR, err, true);
+       emulate_exception(ctxt, PF_VECTOR, 0, true);
 }
 
 static void emulate_ud(struct x86_emulate_ctxt *ctxt)
@@ -834,7 +832,7 @@ static int read_emulated(struct x86_emulate_ctxt *ctxt,
                rc = ops->read_emulated(addr, mc->data + mc->end, n, &err,
                                        ctxt->vcpu);
                if (rc == X86EMUL_PROPAGATE_FAULT)
-                       emulate_pf(ctxt, addr, err);
+                       emulate_pf(ctxt);
                if (rc != X86EMUL_CONTINUE)
                        return rc;
                mc->end += n;
@@ -921,7 +919,7 @@ static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt,
        addr = dt.address + index * 8;
        ret = ops->read_std(addr, desc, sizeof *desc, ctxt->vcpu,  &err);
        if (ret == X86EMUL_PROPAGATE_FAULT)
-               emulate_pf(ctxt, addr, err);
+               emulate_pf(ctxt);
 
        return ret;
 }
@@ -947,7 +945,7 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
        addr = dt.address + index * 8;
        ret = ops->write_std(addr, desc, sizeof *desc, ctxt->vcpu, &err);
        if (ret == X86EMUL_PROPAGATE_FAULT)
-               emulate_pf(ctxt, addr, err);
+               emulate_pf(ctxt);
 
        return ret;
 }
@@ -1117,7 +1115,7 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
                                        &err,
                                        ctxt->vcpu);
                if (rc == X86EMUL_PROPAGATE_FAULT)
-                       emulate_pf(ctxt, c->dst.addr.mem, err);
+                       emulate_pf(ctxt);
                if (rc != X86EMUL_CONTINUE)
                        return rc;
                break;
@@ -1939,7 +1937,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                            &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               emulate_pf(ctxt, old_tss_base, err);
+               emulate_pf(ctxt);
                return ret;
        }
 
@@ -1949,7 +1947,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                             &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               emulate_pf(ctxt, old_tss_base, err);
+               emulate_pf(ctxt);
                return ret;
        }
 
@@ -1957,7 +1955,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                            &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               emulate_pf(ctxt, new_tss_base, err);
+               emulate_pf(ctxt);
                return ret;
        }
 
@@ -1970,7 +1968,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                                     ctxt->vcpu, &err);
                if (ret == X86EMUL_PROPAGATE_FAULT) {
                        /* FIXME: need to provide precise fault address */
-                       emulate_pf(ctxt, new_tss_base, err);
+                       emulate_pf(ctxt);
                        return ret;
                }
        }
@@ -2081,7 +2079,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                            &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               emulate_pf(ctxt, old_tss_base, err);
+               emulate_pf(ctxt);
                return ret;
        }
 
@@ -2091,7 +2089,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                             &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               emulate_pf(ctxt, old_tss_base, err);
+               emulate_pf(ctxt);
                return ret;
        }
 
@@ -2099,7 +2097,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                            &err);
        if (ret == X86EMUL_PROPAGATE_FAULT) {
                /* FIXME: need to provide precise fault address */
-               emulate_pf(ctxt, new_tss_base, err);
+               emulate_pf(ctxt);
                return ret;
        }
 
@@ -2112,7 +2110,7 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                                     ctxt->vcpu, &err);
                if (ret == X86EMUL_PROPAGATE_FAULT) {
                        /* FIXME: need to provide precise fault address */
-                       emulate_pf(ctxt, new_tss_base, err);
+                       emulate_pf(ctxt);
                        return ret;
                }
        }

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 86f7557..9936727 100644 (file)
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2566,11 +2566,9 @@ static unsigned long get_cr3(struct kvm_vcpu *vcpu)
        return vcpu->arch.cr3;
 }
 
-static void inject_page_fault(struct kvm_vcpu *vcpu,
-                             u64 addr,
-                             u32 err_code)
+static void inject_page_fault(struct kvm_vcpu *vcpu)
 {
-       vcpu->arch.mmu.inject_page_fault(vcpu, addr, err_code);
+       vcpu->arch.mmu.inject_page_fault(vcpu);
 }
 
 static void paging_free(struct kvm_vcpu *vcpu)

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 68ee1b7..d07f48a 100644 (file)
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -258,6 +258,10 @@ error:
                walker->error_code |= PFERR_FETCH_MASK;
        if (rsvd_fault)
                walker->error_code |= PFERR_RSVD_MASK;
+
+       vcpu->arch.fault.address    = addr;
+       vcpu->arch.fault.error_code = walker->error_code;
+
        trace_kvm_mmu_walker_error(walker->error_code);
        return 0;
 }
@@ -521,7 +525,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
         */
        if (!r) {
                pgprintk("%s: guest page fault\n", __func__);
-               inject_page_fault(vcpu, addr, walker.error_code);
+               inject_page_fault(vcpu);
                vcpu->arch.last_pt_write_count = 0; /* reset fork detector */
                return 0;
        }

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9d43477..48b74d2 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -329,11 +329,12 @@ void kvm_requeue_exception(struct kvm_vcpu *vcpu, unsigned nr)
 }
 EXPORT_SYMBOL_GPL(kvm_requeue_exception);
 
-void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long addr,
-                          u32 error_code)
+void kvm_inject_page_fault(struct kvm_vcpu *vcpu)
 {
+       unsigned error_code = vcpu->arch.fault.error_code;
+
        ++vcpu->stat.pf_guest;
-       vcpu->arch.cr2 = addr;
+       vcpu->arch.cr2 = vcpu->arch.fault.address;
        kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);
 }
 
@@ -4080,7 +4081,7 @@ static void inject_emulated_exception(struct kvm_vcpu *vcpu)
 {
        struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
        if (ctxt->exception == PF_VECTOR)
-               kvm_inject_page_fault(vcpu, ctxt->cr2, ctxt->error_code);
+               kvm_inject_page_fault(vcpu);
        else if (ctxt->error_code_valid)
                kvm_queue_exception_e(vcpu, ctxt->exception, ctxt->error_code);
        else