KVM: x86 emulator: Provide more callbacks for x86 emulator.

Provide get_cached_descriptor(), set_cached_descriptor(),
get_segment_selector(), set_segment_selector(), get_gdt(),
write_std() callbacks.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 0765725..f901467 100644 (file)
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -63,6 +63,15 @@ struct x86_emulate_ops {
                        unsigned int bytes, struct kvm_vcpu *vcpu, u32 *error);
 
        /*
+        * write_std: Write bytes of standard (non-emulated/special) memory.
+        *            Used for descriptor writing.
+        *  @addr:  [IN ] Linear address to which to write.
+        *  @val:   [OUT] Value write to memory, zero-extended to 'u_long'.
+        *  @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);
+       /*
         * fetch: Read bytes of standard (non-emulated/special) memory.
         *        Used for instruction fetch.
         *  @addr:  [IN ] Linear address from which to read.
@@ -108,6 +117,13 @@ struct x86_emulate_ops {
                                const void *new,
                                unsigned int bytes,
                                struct kvm_vcpu *vcpu);
+       bool (*get_cached_descriptor)(struct desc_struct *desc,
+                                     int seg, struct kvm_vcpu *vcpu);
+       void (*set_cached_descriptor)(struct desc_struct *desc,
+                                     int seg, struct kvm_vcpu *vcpu);
+       u16 (*get_segment_selector)(int seg, struct kvm_vcpu *vcpu);
+       void (*set_segment_selector)(u16 sel, int seg, struct kvm_vcpu *vcpu);
+       void (*get_gdt)(struct desc_ptr *dt, struct kvm_vcpu *vcpu);
        ulong (*get_cr)(int cr, struct kvm_vcpu *vcpu);
        void (*set_cr)(int cr, ulong val, struct kvm_vcpu *vcpu);
        int (*cpl)(struct kvm_vcpu *vcpu);

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0ecd37a..fbee8fb 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3058,6 +3058,18 @@ static int vcpu_mmio_read(struct kvm_vcpu *vcpu, gpa_t addr, int len, void *v)
        return kvm_io_bus_read(vcpu->kvm, KVM_MMIO_BUS, addr, len, v);
 }
 
+static void kvm_set_segment(struct kvm_vcpu *vcpu,
+                       struct kvm_segment *var, int seg)
+{
+       kvm_x86_ops->set_segment(vcpu, var, seg);
+}
+
+void kvm_get_segment(struct kvm_vcpu *vcpu,
+                    struct kvm_segment *var, int seg)
+{
+       kvm_x86_ops->get_segment(vcpu, var, seg);
+}
+
 gpa_t kvm_mmu_gva_to_gpa_read(struct kvm_vcpu *vcpu, gva_t gva, u32 *error)
 {
        u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
@@ -3138,14 +3150,18 @@ static int kvm_read_guest_virt_system(gva_t addr, void *val, unsigned int bytes,
        return kvm_read_guest_virt_helper(addr, val, bytes, vcpu, 0, error);
 }
 
-static int kvm_write_guest_virt(gva_t addr, void *val, unsigned int bytes,
-                               struct kvm_vcpu *vcpu, u32 *error)
+static int kvm_write_guest_virt_helper(gva_t addr, void *val,
+                                      unsigned int bytes,
+                                      struct kvm_vcpu *vcpu, u32 access,
+                                      u32 *error)
 {
        void *data = val;
        int r = X86EMUL_CONTINUE;
 
+       access |= PFERR_WRITE_MASK;
+
        while (bytes) {
-               gpa_t gpa = kvm_mmu_gva_to_gpa_write(vcpu, addr, error);
+               gpa_t gpa =  vcpu->arch.mmu.gva_to_gpa(vcpu, addr, access, error);
                unsigned offset = addr & (PAGE_SIZE-1);
                unsigned towrite = min(bytes, (unsigned)PAGE_SIZE - offset);
                int ret;
@@ -3168,6 +3184,19 @@ out:
        return r;
 }
 
+static int kvm_write_guest_virt(gva_t addr, void *val, unsigned int bytes,
+                               struct kvm_vcpu *vcpu, u32 *error)
+{
+       u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
+       return kvm_write_guest_virt_helper(addr, val, bytes, vcpu, access, error);
+}
+
+static int kvm_write_guest_virt_system(gva_t addr, void *val,
+                                      unsigned int bytes,
+                                      struct kvm_vcpu *vcpu, u32 *error)
+{
+       return kvm_write_guest_virt_helper(addr, val, bytes, vcpu, 0, error);
+}
 
 static int emulator_read_emulated(unsigned long addr,
                                  void *val,
@@ -3484,12 +3513,95 @@ static int emulator_get_cpl(struct kvm_vcpu *vcpu)
        return kvm_x86_ops->get_cpl(vcpu);
 }
 
+static void emulator_get_gdt(struct desc_ptr *dt, struct kvm_vcpu *vcpu)
+{
+       kvm_x86_ops->get_gdt(vcpu, dt);
+}
+
+static bool emulator_get_cached_descriptor(struct desc_struct *desc, int seg,
+                                          struct kvm_vcpu *vcpu)
+{
+       struct kvm_segment var;
+
+       kvm_get_segment(vcpu, &var, seg);
+
+       if (var.unusable)
+               return false;
+
+       if (var.g)
+               var.limit >>= 12;
+       set_desc_limit(desc, var.limit);
+       set_desc_base(desc, (unsigned long)var.base);
+       desc->type = var.type;
+       desc->s = var.s;
+       desc->dpl = var.dpl;
+       desc->p = var.present;
+       desc->avl = var.avl;
+       desc->l = var.l;
+       desc->d = var.db;
+       desc->g = var.g;
+
+       return true;
+}
+
+static void emulator_set_cached_descriptor(struct desc_struct *desc, int seg,
+                                          struct kvm_vcpu *vcpu)
+{
+       struct kvm_segment var;
+
+       /* needed to preserve selector */
+       kvm_get_segment(vcpu, &var, seg);
+
+       var.base = get_desc_base(desc);
+       var.limit = get_desc_limit(desc);
+       if (desc->g)
+               var.limit = (var.limit << 12) | 0xfff;
+       var.type = desc->type;
+       var.present = desc->p;
+       var.dpl = desc->dpl;
+       var.db = desc->d;
+       var.s = desc->s;
+       var.l = desc->l;
+       var.g = desc->g;
+       var.avl = desc->avl;
+       var.present = desc->p;
+       var.unusable = !var.present;
+       var.padding = 0;
+
+       kvm_set_segment(vcpu, &var, seg);
+       return;
+}
+
+static u16 emulator_get_segment_selector(int seg, struct kvm_vcpu *vcpu)
+{
+       struct kvm_segment kvm_seg;
+
+       kvm_get_segment(vcpu, &kvm_seg, seg);
+       return kvm_seg.selector;
+}
+
+static void emulator_set_segment_selector(u16 sel, int seg,
+                                         struct kvm_vcpu *vcpu)
+{
+       struct kvm_segment kvm_seg;
+
+       kvm_get_segment(vcpu, &kvm_seg, seg);
+       kvm_seg.selector = sel;
+       kvm_set_segment(vcpu, &kvm_seg, seg);
+}
+
 static struct x86_emulate_ops emulate_ops = {
        .read_std            = kvm_read_guest_virt_system,
+       .write_std           = kvm_write_guest_virt_system,
        .fetch               = kvm_fetch_guest_virt,
        .read_emulated       = emulator_read_emulated,
        .write_emulated      = emulator_write_emulated,
        .cmpxchg_emulated    = emulator_cmpxchg_emulated,
+       .get_cached_descriptor = emulator_get_cached_descriptor,
+       .set_cached_descriptor = emulator_set_cached_descriptor,
+       .get_segment_selector = emulator_get_segment_selector,
+       .set_segment_selector = emulator_set_segment_selector,
+       .get_gdt             = emulator_get_gdt,
        .get_cr              = emulator_get_cr,
        .set_cr              = emulator_set_cr,
        .cpl                 = emulator_get_cpl,
@@ -4649,12 +4761,6 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
        return 0;
 }
 
-void kvm_get_segment(struct kvm_vcpu *vcpu,
-                    struct kvm_segment *var, int seg)
-{
-       kvm_x86_ops->get_segment(vcpu, var, seg);
-}
-
 void kvm_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)
 {
        struct kvm_segment cs;
@@ -4726,12 +4832,6 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
        return 0;
 }
 
-static void kvm_set_segment(struct kvm_vcpu *vcpu,
-                       struct kvm_segment *var, int seg)
-{
-       kvm_x86_ops->set_segment(vcpu, var, seg);
-}
-
 static void seg_desct_to_kvm_desct(struct desc_struct *seg_desc, u16 selector,
                                   struct kvm_segment *kvm_desct)
 {