KVM: x86 emulator: make emulator memory callbacks return full exception

This way, they can return #GP, not just #PF.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

3 files changed, 84 insertions, 96 deletions

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index b7c11270ae8f..87d017e276f4 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -70,7 +70,8 @@ struct x86_emulate_ops {
          *  @bytes: [IN ] Number of bytes to read from memory.
          */
         int (*read_std)(unsigned long addr, void *val,
-                        unsigned int bytes, struct kvm_vcpu *vcpu, u32 *error);
+                        unsigned int bytes, struct kvm_vcpu *vcpu,
+                        struct x86_exception *fault);
 
         /*
          * write_std: Write bytes of standard (non-emulated/special) memory.
@@ -80,7 +81,8 @@ struct x86_emulate_ops {
          *  @bytes: [IN ] Number of bytes to write to memory.
          */
         int (*write_std)(unsigned long addr, void *val,
-                         unsigned int bytes, struct kvm_vcpu *vcpu, u32 *error);
+                         unsigned int bytes, struct kvm_vcpu *vcpu,
+                         struct x86_exception *fault);
         /*
          * fetch: Read bytes of standard (non-emulated/special) memory.
          *        Used for instruction fetch.
@@ -89,7 +91,8 @@ struct x86_emulate_ops {
          *  @bytes: [IN ] Number of bytes to read from memory.
          */
         int (*fetch)(unsigned long addr, void *val,
-                        unsigned int bytes, struct kvm_vcpu *vcpu, u32 *error);
+                     unsigned int bytes, struct kvm_vcpu *vcpu,
+                     struct x86_exception *fault);
 
         /*
          * read_emulated: Read bytes from emulated/special memory area.
@@ -100,7 +103,7 @@ struct x86_emulate_ops {
         int (*read_emulated)(unsigned long addr,
                              void *val,
                              unsigned int bytes,
-                             unsigned int *error,
+                             struct x86_exception *fault,
                              struct kvm_vcpu *vcpu);
 
         /*
@@ -113,7 +116,7 @@ struct x86_emulate_ops {
         int (*write_emulated)(unsigned long addr,
                               const void *val,
                               unsigned int bytes,
-                              unsigned int *error,
+                              struct x86_exception *fault,
                               struct kvm_vcpu *vcpu);
 
         /*
@@ -128,7 +131,7 @@ struct x86_emulate_ops {
                                 const void *old,
                                 const void *new,
                                 unsigned int bytes,
-                                unsigned int *error,
+                                struct x86_exception *fault,
                                 struct kvm_vcpu *vcpu);
 
         int (*pio_in_emulated)(int size, unsigned short port, void *val,
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 18596e6649aa..16ed6c178bb2 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -512,7 +512,7 @@ static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
                 cur_size = fc->end - fc->start;
                 size = min(15UL - cur_size, PAGE_SIZE - offset_in_page(eip));
                 rc = ops->fetch(ctxt->cs_base + eip, fc->data + cur_size,
-                                size, ctxt->vcpu, NULL);
+                                size, ctxt->vcpu, &ctxt->exception);
                 if (rc != X86EMUL_CONTINUE)
                         return rc;
                 fc->end += size;
@@ -565,12 +565,12 @@ static int read_descriptor(struct x86_emulate_ctxt *ctxt,
                 op_bytes = 3;
         *address = 0;
         rc = ops->read_std(linear(ctxt, addr), (unsigned long *)size, 2,
-                           ctxt->vcpu, NULL);
+                           ctxt->vcpu, &ctxt->exception);
         if (rc != X86EMUL_CONTINUE)
                 return rc;
         addr.ea += 2;
         rc = ops->read_std(linear(ctxt, addr), address, op_bytes,
-                           ctxt->vcpu, NULL);
+                           ctxt->vcpu, &ctxt->exception);
         return rc;
 }
 
@@ -816,7 +816,6 @@ static int read_emulated(struct x86_emulate_ctxt *ctxt,
 {
         int rc;
         struct read_cache *mc = &ctxt->decode.mem_read;
-        u32 err;
 
         while (size) {
                 int n = min(size, 8u);
@@ -824,10 +823,8 @@ static int read_emulated(struct x86_emulate_ctxt *ctxt,
                 if (mc->pos < mc->end)
                         goto read_cached;
 
-                rc = ops->read_emulated(addr, mc->data + mc->end, n, &err,
-                                        ctxt->vcpu);
-                if (rc == X86EMUL_PROPAGATE_FAULT)
-                        emulate_pf(ctxt);
+                rc = ops->read_emulated(addr, mc->data + mc->end, n,
+                                        &ctxt->exception, ctxt->vcpu);
                 if (rc != X86EMUL_CONTINUE)
                         return rc;
                 mc->end += n;
@@ -902,7 +899,6 @@ static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt,
         struct desc_ptr dt;
         u16 index = selector >> 3;
         int ret;
-        u32 err;
         ulong addr;
 
         get_descriptor_table_ptr(ctxt, ops, selector, &dt);
@@ -912,9 +908,8 @@ static int read_segment_descriptor(struct x86_emulate_ctxt *ctxt,
                 return X86EMUL_PROPAGATE_FAULT;
         }
         addr = dt.address + index * 8;
-        ret = ops->read_std(addr, desc, sizeof *desc, ctxt->vcpu,  &err);
-        if (ret == X86EMUL_PROPAGATE_FAULT)
-                emulate_pf(ctxt);
+        ret = ops->read_std(addr, desc, sizeof *desc, ctxt->vcpu,
+                            &ctxt->exception);
 
        return ret;
 }
@@ -926,7 +921,6 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
 {
         struct desc_ptr dt;
         u16 index = selector >> 3;
-        u32 err;
         ulong addr;
         int ret;
 
@@ -938,9 +932,8 @@ 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);
+        ret = ops->write_std(addr, desc, sizeof *desc, ctxt->vcpu,
+                             &ctxt->exception);
 
         return ret;
 }
@@ -1087,7 +1080,6 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
 {
         int rc;
         struct decode_cache *c = &ctxt->decode;
-        u32 err;
 
         switch (c->dst.type) {
         case OP_REG:
@@ -1100,17 +1092,15 @@ static inline int writeback(struct x86_emulate_ctxt *ctxt,
                                         &c->dst.orig_val,
                                         &c->dst.val,
                                         c->dst.bytes,
-                                        &err,
+                                        &ctxt->exception,
                                         ctxt->vcpu);
                 else
                         rc = ops->write_emulated(
                                         linear(ctxt, c->dst.addr.mem),
                                         &c->dst.val,
                                         c->dst.bytes,
-                                        &err,
+                                        &ctxt->exception,
                                         ctxt->vcpu);
-                if (rc == X86EMUL_PROPAGATE_FAULT)
-                        emulate_pf(ctxt);
                 if (rc != X86EMUL_CONTINUE)
                         return rc;
                 break;
@@ -1283,7 +1273,6 @@ int emulate_int_real(struct x86_emulate_ctxt *ctxt,
         gva_t cs_addr;
         gva_t eip_addr;
         u16 cs, eip;
-        u32 err;
 
         /* TODO: Add limit checks */
         c->src.val = ctxt->eflags;
@@ -1313,11 +1302,11 @@ int emulate_int_real(struct x86_emulate_ctxt *ctxt,
         eip_addr = dt.address + (irq << 2);
         cs_addr = dt.address + (irq << 2) + 2;
 
-        rc = ops->read_std(cs_addr, &cs, 2, ctxt->vcpu, &err);
+        rc = ops->read_std(cs_addr, &cs, 2, ctxt->vcpu, &ctxt->exception);
         if (rc != X86EMUL_CONTINUE)
                 return rc;
 
-        rc = ops->read_std(eip_addr, &eip, 2, ctxt->vcpu, &err);
+        rc = ops->read_std(eip_addr, &eip, 2, ctxt->vcpu, &ctxt->exception);
         if (rc != X86EMUL_CONTINUE)
                 return rc;
 
@@ -1930,33 +1919,27 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
 {
         struct tss_segment_16 tss_seg;
         int ret;
-        u32 err, new_tss_base = get_desc_base(new_desc);
+        u32 new_tss_base = get_desc_base(new_desc);
 
         ret = ops->read_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
-                            &err);
-        if (ret == X86EMUL_PROPAGATE_FAULT) {
+                            &ctxt->exception);
+        if (ret == X86EMUL_PROPAGATE_FAULT)
                 /* FIXME: need to provide precise fault address */
-                emulate_pf(ctxt);
                 return ret;
-        }
 
         save_state_to_tss16(ctxt, ops, &tss_seg);
 
         ret = ops->write_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
-                             &err);
-        if (ret == X86EMUL_PROPAGATE_FAULT) {
+                             &ctxt->exception);
+        if (ret == X86EMUL_PROPAGATE_FAULT)
                 /* FIXME: need to provide precise fault address */
-                emulate_pf(ctxt);
                 return ret;
-        }
 
         ret = ops->read_std(new_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
-                            &err);
-        if (ret == X86EMUL_PROPAGATE_FAULT) {
+                            &ctxt->exception);
+        if (ret == X86EMUL_PROPAGATE_FAULT)
                 /* FIXME: need to provide precise fault address */
-                emulate_pf(ctxt);
                 return ret;
-        }
 
         if (old_tss_sel != 0xffff) {
                 tss_seg.prev_task_link = old_tss_sel;
@@ -1964,12 +1947,10 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
                 ret = ops->write_std(new_tss_base,
                                      &tss_seg.prev_task_link,
                                      sizeof tss_seg.prev_task_link,
-                                     ctxt->vcpu, &err);
-                if (ret == X86EMUL_PROPAGATE_FAULT) {
+                                     ctxt->vcpu, &ctxt->exception);
+                if (ret == X86EMUL_PROPAGATE_FAULT)
                         /* FIXME: need to provide precise fault address */
-                        emulate_pf(ctxt);
                         return ret;
-                }
         }
 
         return load_state_from_tss16(ctxt, ops, &tss_seg);
@@ -2072,33 +2053,27 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
 {
         struct tss_segment_32 tss_seg;
         int ret;
-        u32 err, new_tss_base = get_desc_base(new_desc);
+        u32 new_tss_base = get_desc_base(new_desc);
 
         ret = ops->read_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
-                            &err);
-        if (ret == X86EMUL_PROPAGATE_FAULT) {
+                            &ctxt->exception);
+        if (ret == X86EMUL_PROPAGATE_FAULT)
                 /* FIXME: need to provide precise fault address */
-                emulate_pf(ctxt);
                 return ret;
-        }
 
         save_state_to_tss32(ctxt, ops, &tss_seg);
 
         ret = ops->write_std(old_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
-                             &err);
-        if (ret == X86EMUL_PROPAGATE_FAULT) {
+                             &ctxt->exception);
+        if (ret == X86EMUL_PROPAGATE_FAULT)
                 /* FIXME: need to provide precise fault address */
-                emulate_pf(ctxt);
                 return ret;
-        }
 
         ret = ops->read_std(new_tss_base, &tss_seg, sizeof tss_seg, ctxt->vcpu,
-                            &err);
-        if (ret == X86EMUL_PROPAGATE_FAULT) {
+                            &ctxt->exception);
+        if (ret == X86EMUL_PROPAGATE_FAULT)
                 /* FIXME: need to provide precise fault address */
-                emulate_pf(ctxt);
                 return ret;
-        }
 
         if (old_tss_sel != 0xffff) {
                 tss_seg.prev_task_link = old_tss_sel;
@@ -2106,12 +2081,10 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
                 ret = ops->write_std(new_tss_base,
                                      &tss_seg.prev_task_link,
                                      sizeof tss_seg.prev_task_link,
-                                     ctxt->vcpu, &err);
-                if (ret == X86EMUL_PROPAGATE_FAULT) {
+                                     ctxt->vcpu, &ctxt->exception);
+                if (ret == X86EMUL_PROPAGATE_FAULT)
                         /* FIXME: need to provide precise fault address */
-                        emulate_pf(ctxt);
                         return ret;
-                }
         }
 
         return load_state_from_tss32(ctxt, ops, &tss_seg);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0c908321e900..8311ed909c49 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3642,24 +3642,31 @@ gpa_t kvm_mmu_gva_to_gpa_system(struct kvm_vcpu *vcpu, gva_t gva, u32 *error)
         return vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, 0, error);
 }
 
+static int make_page_fault(struct x86_exception *exception, u32 error)
+{
+        exception->vector = PF_VECTOR;
+        exception->error_code_valid = true;
+        exception->error_code = error;
+        return X86EMUL_PROPAGATE_FAULT;
+}
+
 static int kvm_read_guest_virt_helper(gva_t addr, void *val, unsigned int bytes,
                                       struct kvm_vcpu *vcpu, u32 access,
-                                      u32 *error)
+                                      struct x86_exception *exception)
 {
         void *data = val;
         int r = X86EMUL_CONTINUE;
+        u32 error;
 
         while (bytes) {
                 gpa_t gpa = vcpu->arch.walk_mmu->gva_to_gpa(vcpu, addr, access,
-                                                            error);
+                                                            &error);
                 unsigned offset = addr & (PAGE_SIZE-1);
                 unsigned toread = min(bytes, (unsigned)PAGE_SIZE - offset);
                 int ret;
 
-                if (gpa == UNMAPPED_GVA) {
-                        r = X86EMUL_PROPAGATE_FAULT;
-                        goto out;
-                }
+                if (gpa == UNMAPPED_GVA)
+                        return make_page_fault(exception, error);
                 ret = kvm_read_guest(vcpu->kvm, gpa, data, toread);
                 if (ret < 0) {
                         r = X86EMUL_IO_NEEDED;
@@ -3676,47 +3683,50 @@ out:
 
 /* used for instruction fetching */
 static int kvm_fetch_guest_virt(gva_t addr, void *val, unsigned int bytes,
-                                struct kvm_vcpu *vcpu, u32 *error)
+                                struct kvm_vcpu *vcpu,
+                                struct x86_exception *exception)
 {
         u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
         return kvm_read_guest_virt_helper(addr, val, bytes, vcpu,
-                                          access | PFERR_FETCH_MASK, error);
+                                          access | PFERR_FETCH_MASK,
+                                          exception);
 }
 
 static int kvm_read_guest_virt(gva_t addr, void *val, unsigned int bytes,
-                               struct kvm_vcpu *vcpu, u32 *error)
+                               struct kvm_vcpu *vcpu,
+                               struct x86_exception *exception)
 {
         u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
         return kvm_read_guest_virt_helper(addr, val, bytes, vcpu, access,
-                                          error);
+                                          exception);
 }
 
 static int kvm_read_guest_virt_system(gva_t addr, void *val, unsigned int bytes,
-                               struct kvm_vcpu *vcpu, u32 *error)
+                                      struct kvm_vcpu *vcpu,
+                                      struct x86_exception *exception)
 {
-        return kvm_read_guest_virt_helper(addr, val, bytes, vcpu, 0, error);
+        return kvm_read_guest_virt_helper(addr, val, bytes, vcpu, 0, exception);
 }
 
 static int kvm_write_guest_virt_system(gva_t addr, void *val,
                                        unsigned int bytes,
                                        struct kvm_vcpu *vcpu,
-                                       u32 *error)
+                                       struct x86_exception *exception)
 {
         void *data = val;
         int r = X86EMUL_CONTINUE;
+        u32 error;
 
         while (bytes) {
                 gpa_t gpa =  vcpu->arch.walk_mmu->gva_to_gpa(vcpu, addr,
                                                              PFERR_WRITE_MASK,
-                                                             error);
+                                                             &error);
                 unsigned offset = addr & (PAGE_SIZE-1);
                 unsigned towrite = min(bytes, (unsigned)PAGE_SIZE - offset);
                 int ret;
 
-                if (gpa == UNMAPPED_GVA) {
-                        r = X86EMUL_PROPAGATE_FAULT;
-                        goto out;
-                }
+                if (gpa == UNMAPPED_GVA)
+                        return make_page_fault(exception, error);
                 ret = kvm_write_guest(vcpu->kvm, gpa, data, towrite);
                 if (ret < 0) {
                         r = X86EMUL_IO_NEEDED;
@@ -3734,10 +3744,11 @@ out:
 static int emulator_read_emulated(unsigned long addr,
                                   void *val,
                                   unsigned int bytes,
-                                  unsigned int *error_code,
+                                  struct x86_exception *exception,
                                   struct kvm_vcpu *vcpu)
 {
         gpa_t                 gpa;
+        u32 error_code;
 
         if (vcpu->mmio_read_completed) {
                 memcpy(val, vcpu->mmio_data, bytes);
@@ -3747,17 +3758,17 @@ static int emulator_read_emulated(unsigned long addr,
                 return X86EMUL_CONTINUE;
         }
 
-        gpa = kvm_mmu_gva_to_gpa_read(vcpu, addr, error_code);
+        gpa = kvm_mmu_gva_to_gpa_read(vcpu, addr, &error_code);
 
         if (gpa == UNMAPPED_GVA)
-                return X86EMUL_PROPAGATE_FAULT;
+                return make_page_fault(exception, error_code);
 
         /* For APIC access vmexit */
         if ((gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
                 goto mmio;
 
-        if (kvm_read_guest_virt(addr, val, bytes, vcpu, NULL)
-                                == X86EMUL_CONTINUE)
+        if (kvm_read_guest_virt(addr, val, bytes, vcpu, exception)
+            == X86EMUL_CONTINUE)
                 return X86EMUL_CONTINUE;
 
 mmio:
@@ -3781,7 +3792,7 @@ mmio:
 }
 
 int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
-                          const void *val, int bytes)
+                        const void *val, int bytes)
 {
         int ret;
 
@@ -3795,15 +3806,16 @@ int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
 static int emulator_write_emulated_onepage(unsigned long addr,
                                            const void *val,
                                            unsigned int bytes,
-                                           unsigned int *error_code,
+                                           struct x86_exception *exception,
                                            struct kvm_vcpu *vcpu)
 {
         gpa_t                 gpa;
+        u32 error_code;
 
-        gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, error_code);
+        gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, &error_code);
 
         if (gpa == UNMAPPED_GVA)
-                return X86EMUL_PROPAGATE_FAULT;
+                return make_page_fault(exception, error_code);
 
         /* For APIC access vmexit */
         if ((gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
@@ -3833,7 +3845,7 @@ mmio:
 int emulator_write_emulated(unsigned long addr,
                             const void *val,
                             unsigned int bytes,
-                            unsigned int *error_code,
+                            struct x86_exception *exception,
                             struct kvm_vcpu *vcpu)
 {
         /* Crossing a page boundary? */
@@ -3841,7 +3853,7 @@ int emulator_write_emulated(unsigned long addr,
                 int rc, now;
 
                 now = -addr & ~PAGE_MASK;
-                rc = emulator_write_emulated_onepage(addr, val, now, error_code,
+                rc = emulator_write_emulated_onepage(addr, val, now, exception,
                                                      vcpu);
                 if (rc != X86EMUL_CONTINUE)
                         return rc;
@@ -3849,7 +3861,7 @@ int emulator_write_emulated(unsigned long addr,
                 val += now;
                 bytes -= now;
         }
-        return emulator_write_emulated_onepage(addr, val, bytes, error_code,
+        return emulator_write_emulated_onepage(addr, val, bytes, exception,
                                                vcpu);
 }
 
@@ -3867,7 +3879,7 @@ static int emulator_cmpxchg_emulated(unsigned long addr,
                                      const void *old,
                                      const void *new,
                                      unsigned int bytes,
-                                     unsigned int *error_code,
+                                     struct x86_exception *exception,
                                      struct kvm_vcpu *vcpu)
 {
         gpa_t gpa;
@@ -3925,7 +3937,7 @@ static int emulator_cmpxchg_emulated(unsigned long addr,
 emul_write:
         printk_once(KERN_WARNING "kvm: emulating exchange as write\n");
 
-        return emulator_write_emulated(addr, new, bytes, error_code, vcpu);
+        return emulator_write_emulated(addr, new, bytes, exception, vcpu);
 }
 
 static int kernel_pio(struct kvm_vcpu *vcpu, void *pd)