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KVM: x86 emulator: Provide more callbacks for x86 emulator.
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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>
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Gleb Natapov authored and Avi Kivity committed May 17, 2010
1 parent aca06a8 commit 2dafc6c
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Showing 2 changed files with 131 additions and 15 deletions.
16 changes: 16 additions & 0 deletions arch/x86/include/asm/kvm_emulate.h
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Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,15 @@ struct x86_emulate_ops {
int (*read_std)(unsigned long addr, void *val,
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.
Expand Down Expand Up @@ -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);
Expand Down
130 changes: 115 additions & 15 deletions arch/x86/kvm/x86.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand All @@ -3168,6 +3184,19 @@ static int kvm_write_guest_virt(gva_t addr, void *val, unsigned int bytes,
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,
Expand Down Expand Up @@ -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,
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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)
{
Expand Down

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