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KVM: SVM: Add intercept check for accessing dr registers

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This patch adds the intercept checks for instruction
accessing the debug registers.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Joerg Roedel 2011-04-04 12:39:29 +02:00 committed by Avi Kivity
parent cfec82cb7d
commit 3b88e41a41
3 changed files with 56 additions and 15 deletions
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2
arch/x86/include/asm/kvm_emulate.h
View File

@ -309,6 +309,8 @@ enum x86_intercept {
x86_intercept_clts,
x86_intercept_lmsw,
x86_intercept_smsw,
x86_intercept_dr_read,
x86_intercept_dr_write,
x86_intercept_lidt,
x86_intercept_sidt,
x86_intercept_lgdt,

63
arch/x86/kvm/emulate.c
View File

@ -509,6 +509,11 @@ static int emulate_exception(struct x86_emulate_ctxt *ctxt, int vec,
return X86EMUL_PROPAGATE_FAULT;
}
static int emulate_db(struct x86_emulate_ctxt *ctxt)
{
return emulate_exception(ctxt, DB_VECTOR, 0, false);
}
static int emulate_gp(struct x86_emulate_ctxt *ctxt, int err)
{
return emulate_exception(ctxt, GP_VECTOR, err, true);
@ -2534,6 +2539,47 @@ static int check_cr_write(struct x86_emulate_ctxt *ctxt)
return X86EMUL_CONTINUE;
}
static int check_dr7_gd(struct x86_emulate_ctxt *ctxt)
{
unsigned long dr7;
ctxt->ops->get_dr(7, &dr7, ctxt->vcpu);
/* Check if DR7.Global_Enable is set */
return dr7 & (1 << 13);
}
static int check_dr_read(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
int dr = c->modrm_reg;
u64 cr4;
if (dr > 7)
return emulate_ud(ctxt);
cr4 = ctxt->ops->get_cr(4, ctxt->vcpu);
if ((cr4 & X86_CR4_DE) && (dr == 4 || dr == 5))
return emulate_ud(ctxt);
if (check_dr7_gd(ctxt))
return emulate_db(ctxt);
return X86EMUL_CONTINUE;
}
static int check_dr_write(struct x86_emulate_ctxt *ctxt)
{
struct decode_cache *c = &ctxt->decode;
u64 new_val = c->src.val64;
int dr = c->modrm_reg;
if ((dr == 6 || dr == 7) && (new_val & 0xffffffff00000000ULL))
return emulate_gp(ctxt, 0);
return check_dr_read(ctxt);
}
#define D(_y) { .flags = (_y) }
#define DI(_y, _i) { .flags = (_y), .intercept = x86_intercept_##_i }
#define DIP(_y, _i, _p) { .flags = (_y), .intercept = x86_intercept_##_i, \
@ -2728,9 +2774,9 @@ static struct opcode twobyte_table[256] = {
N, N, N, N, N, N, N, N, D(ImplicitOps | ModRM), N, N, N, N, N, N, N,
/* 0x20 - 0x2F */
DIP(ModRM | DstMem | Priv | Op3264, cr_read, check_cr_read),
D(ModRM | DstMem | Priv | Op3264),
DIP(ModRM | DstMem | Priv | Op3264, dr_read, check_dr_read),
DIP(ModRM | SrcMem | Priv | Op3264, cr_write, check_cr_write),
D(ModRM | SrcMem | Priv | Op3264),
DIP(ModRM | SrcMem | Priv | Op3264, dr_write, check_dr_write),
N, N, N, N,
N, N, N, N, N, N, N, N,
/* 0x30 - 0x3F */
@ -3818,12 +3864,6 @@ twobyte_insn:
c->dst.val = ops->get_cr(c->modrm_reg, ctxt->vcpu);
break;
case 0x21: /* mov from dr to reg */
if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
(c->modrm_reg == 4 || c->modrm_reg == 5)) {
emulate_ud(ctxt);
rc = X86EMUL_PROPAGATE_FAULT;
goto done;
}
ops->get_dr(c->modrm_reg, &c->dst.val, ctxt->vcpu);
break;
case 0x22: /* mov reg, cr */
@ -3835,13 +3875,6 @@ twobyte_insn:
c->dst.type = OP_NONE;
break;
case 0x23: /* mov from reg to dr */
if ((ops->get_cr(4, ctxt->vcpu) & X86_CR4_DE) &&
(c->modrm_reg == 4 || c->modrm_reg == 5)) {
emulate_ud(ctxt);
rc = X86EMUL_PROPAGATE_FAULT;
goto done;
}
if (ops->set_dr(c->modrm_reg, c->src.val &
((ctxt->mode == X86EMUL_MODE_PROT64) ?
~0ULL : ~0U), ctxt->vcpu) < 0) {

6
arch/x86/kvm/svm.c
View File

@ -3882,6 +3882,8 @@ static struct __x86_intercept {
[x86_intercept_clts] = POST_EX(SVM_EXIT_WRITE_CR0),
[x86_intercept_lmsw] = POST_EX(SVM_EXIT_WRITE_CR0),
[x86_intercept_smsw] = POST_EX(SVM_EXIT_READ_CR0),
[x86_intercept_dr_read] = POST_EX(SVM_EXIT_READ_DR0),
[x86_intercept_dr_write] = POST_EX(SVM_EXIT_WRITE_DR0),
};
#undef POST_EX
@ -3939,6 +3941,10 @@ static int svm_check_intercept(struct kvm_vcpu *vcpu,
break;
}
case SVM_EXIT_READ_DR0:
case SVM_EXIT_WRITE_DR0:
icpt_info.exit_code += info->modrm_reg;
break;
default:
break;
}