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Diffstat (limited to 'arch/x86/kvm/x86_emulate.c')
-rw-r--r--arch/x86/kvm/x86_emulate.c257
1 files changed, 254 insertions, 3 deletions
diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index 616de4628d60..c6663d46f328 100644
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -32,6 +32,8 @@
#include <linux/module.h>
#include <asm/kvm_x86_emulate.h>
+#include "mmu.h" /* for is_long_mode() */
+
/*
* Opcode effective-address decode tables.
* Note that we only emulate instructions that have at least one memory
@@ -60,6 +62,7 @@
#define SrcImmByte (6<<4) /* 8-bit sign-extended immediate operand. */
#define SrcOne (7<<4) /* Implied '1' */
#define SrcImmUByte (8<<4) /* 8-bit unsigned immediate operand. */
+#define SrcImmU (9<<4) /* Immediate operand, unsigned */
#define SrcMask (0xf<<4)
/* Generic ModRM decode. */
#define ModRM (1<<8)
@@ -195,7 +198,7 @@ static u32 opcode_table[256] = {
ByteOp | SrcImmUByte, SrcImmUByte,
/* 0xE8 - 0xEF */
SrcImm | Stack, SrcImm | ImplicitOps,
- SrcImm | Src2Imm16, SrcImmByte | ImplicitOps,
+ SrcImmU | Src2Imm16, SrcImmByte | ImplicitOps,
SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
SrcNone | ByteOp | ImplicitOps, SrcNone | ImplicitOps,
/* 0xF0 - 0xF7 */
@@ -208,7 +211,7 @@ static u32 opcode_table[256] = {
static u32 twobyte_table[256] = {
/* 0x00 - 0x0F */
- 0, Group | GroupDual | Group7, 0, 0, 0, 0, ImplicitOps, 0,
+ 0, Group | GroupDual | Group7, 0, 0, 0, ImplicitOps, ImplicitOps, 0,
ImplicitOps, ImplicitOps, 0, 0, 0, ImplicitOps | ModRM, 0, 0,
/* 0x10 - 0x1F */
0, 0, 0, 0, 0, 0, 0, 0, ImplicitOps | ModRM, 0, 0, 0, 0, 0, 0, 0,
@@ -216,7 +219,9 @@ static u32 twobyte_table[256] = {
ModRM | ImplicitOps, ModRM, ModRM | ImplicitOps, ModRM, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
/* 0x30 - 0x3F */
- ImplicitOps, 0, ImplicitOps, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ ImplicitOps, 0, ImplicitOps, 0,
+ ImplicitOps, ImplicitOps, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0,
/* 0x40 - 0x47 */
DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
@@ -319,8 +324,11 @@ static u32 group2_table[] = {
};
/* EFLAGS bit definitions. */
+#define EFLG_VM (1<<17)
+#define EFLG_RF (1<<16)
#define EFLG_OF (1<<11)
#define EFLG_DF (1<<10)
+#define EFLG_IF (1<<9)
#define EFLG_SF (1<<7)
#define EFLG_ZF (1<<6)
#define EFLG_AF (1<<4)
@@ -1027,6 +1035,7 @@ done_prefixes:
c->src.type = OP_MEM;
break;
case SrcImm:
+ case SrcImmU:
c->src.type = OP_IMM;
c->src.ptr = (unsigned long *)c->eip;
c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
@@ -1044,6 +1053,19 @@ done_prefixes:
c->src.val = insn_fetch(s32, 4, c->eip);
break;
}
+ if ((c->d & SrcMask) == SrcImmU) {
+ switch (c->src.bytes) {
+ case 1:
+ c->src.val &= 0xff;
+ break;
+ case 2:
+ c->src.val &= 0xffff;
+ break;
+ case 4:
+ c->src.val &= 0xffffffff;
+ break;
+ }
+ }
break;
case SrcImmByte:
case SrcImmUByte:
@@ -1375,6 +1397,217 @@ static void toggle_interruptibility(struct x86_emulate_ctxt *ctxt, u32 mask)
ctxt->interruptibility = mask;
}
+static inline void
+setup_syscalls_segments(struct x86_emulate_ctxt *ctxt,
+ struct kvm_segment *cs, struct kvm_segment *ss)
+{
+ memset(cs, 0, sizeof(struct kvm_segment));
+ kvm_x86_ops->get_segment(ctxt->vcpu, cs, VCPU_SREG_CS);
+ memset(ss, 0, sizeof(struct kvm_segment));
+
+ cs->l = 0; /* will be adjusted later */
+ cs->base = 0; /* flat segment */
+ cs->g = 1; /* 4kb granularity */
+ cs->limit = 0xffffffff; /* 4GB limit */
+ cs->type = 0x0b; /* Read, Execute, Accessed */
+ cs->s = 1;
+ cs->dpl = 0; /* will be adjusted later */
+ cs->present = 1;
+ cs->db = 1;
+
+ ss->unusable = 0;
+ ss->base = 0; /* flat segment */
+ ss->limit = 0xffffffff; /* 4GB limit */
+ ss->g = 1; /* 4kb granularity */
+ ss->s = 1;
+ ss->type = 0x03; /* Read/Write, Accessed */
+ ss->db = 1; /* 32bit stack segment */
+ ss->dpl = 0;
+ ss->present = 1;
+}
+
+static int
+emulate_syscall(struct x86_emulate_ctxt *ctxt)
+{
+ struct decode_cache *c = &ctxt->decode;
+ struct kvm_segment cs, ss;
+ u64 msr_data;
+
+ /* syscall is not available in real mode */
+ if (c->lock_prefix || ctxt->mode == X86EMUL_MODE_REAL
+ || !(ctxt->vcpu->arch.cr0 & X86_CR0_PE))
+ return -1;
+
+ setup_syscalls_segments(ctxt, &cs, &ss);
+
+ kvm_x86_ops->get_msr(ctxt->vcpu, MSR_STAR, &msr_data);
+ msr_data >>= 32;
+ cs.selector = (u16)(msr_data & 0xfffc);
+ ss.selector = (u16)(msr_data + 8);
+
+ if (is_long_mode(ctxt->vcpu)) {
+ cs.db = 0;
+ cs.l = 1;
+ }
+ kvm_x86_ops->set_segment(ctxt->vcpu, &cs, VCPU_SREG_CS);
+ kvm_x86_ops->set_segment(ctxt->vcpu, &ss, VCPU_SREG_SS);
+
+ c->regs[VCPU_REGS_RCX] = c->eip;
+ if (is_long_mode(ctxt->vcpu)) {
+#ifdef CONFIG_X86_64
+ c->regs[VCPU_REGS_R11] = ctxt->eflags & ~EFLG_RF;
+
+ kvm_x86_ops->get_msr(ctxt->vcpu,
+ ctxt->mode == X86EMUL_MODE_PROT64 ?
+ MSR_LSTAR : MSR_CSTAR, &msr_data);
+ c->eip = msr_data;
+
+ kvm_x86_ops->get_msr(ctxt->vcpu, MSR_SYSCALL_MASK, &msr_data);
+ ctxt->eflags &= ~(msr_data | EFLG_RF);
+#endif
+ } else {
+ /* legacy mode */
+ kvm_x86_ops->get_msr(ctxt->vcpu, MSR_STAR, &msr_data);
+ c->eip = (u32)msr_data;
+
+ ctxt->eflags &= ~(EFLG_VM | EFLG_IF | EFLG_RF);
+ }
+
+ return 0;
+}
+
+static int
+emulate_sysenter(struct x86_emulate_ctxt *ctxt)
+{
+ struct decode_cache *c = &ctxt->decode;
+ struct kvm_segment cs, ss;
+ u64 msr_data;
+
+ /* inject #UD if LOCK prefix is used */
+ if (c->lock_prefix)
+ return -1;
+
+ /* inject #GP if in real mode or paging is disabled */
+ if (ctxt->mode == X86EMUL_MODE_REAL ||
+ !(ctxt->vcpu->arch.cr0 & X86_CR0_PE)) {
+ kvm_inject_gp(ctxt->vcpu, 0);
+ return -1;
+ }
+
+ /* XXX sysenter/sysexit have not been tested in 64bit mode.
+ * Therefore, we inject an #UD.
+ */
+ if (ctxt->mode == X86EMUL_MODE_PROT64)
+ return -1;
+
+ setup_syscalls_segments(ctxt, &cs, &ss);
+
+ kvm_x86_ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_CS, &msr_data);
+ switch (ctxt->mode) {
+ case X86EMUL_MODE_PROT32:
+ if ((msr_data & 0xfffc) == 0x0) {
+ kvm_inject_gp(ctxt->vcpu, 0);
+ return -1;
+ }
+ break;
+ case X86EMUL_MODE_PROT64:
+ if (msr_data == 0x0) {
+ kvm_inject_gp(ctxt->vcpu, 0);
+ return -1;
+ }
+ break;
+ }
+
+ ctxt->eflags &= ~(EFLG_VM | EFLG_IF | EFLG_RF);
+ cs.selector = (u16)msr_data;
+ cs.selector &= ~SELECTOR_RPL_MASK;
+ ss.selector = cs.selector + 8;
+ ss.selector &= ~SELECTOR_RPL_MASK;
+ if (ctxt->mode == X86EMUL_MODE_PROT64
+ || is_long_mode(ctxt->vcpu)) {
+ cs.db = 0;
+ cs.l = 1;
+ }
+
+ kvm_x86_ops->set_segment(ctxt->vcpu, &cs, VCPU_SREG_CS);
+ kvm_x86_ops->set_segment(ctxt->vcpu, &ss, VCPU_SREG_SS);
+
+ kvm_x86_ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_EIP, &msr_data);
+ c->eip = msr_data;
+
+ kvm_x86_ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_ESP, &msr_data);
+ c->regs[VCPU_REGS_RSP] = msr_data;
+
+ return 0;
+}
+
+static int
+emulate_sysexit(struct x86_emulate_ctxt *ctxt)
+{
+ struct decode_cache *c = &ctxt->decode;
+ struct kvm_segment cs, ss;
+ u64 msr_data;
+ int usermode;
+
+ /* inject #UD if LOCK prefix is used */
+ if (c->lock_prefix)
+ return -1;
+
+ /* inject #GP if in real mode or paging is disabled */
+ if (ctxt->mode == X86EMUL_MODE_REAL
+ || !(ctxt->vcpu->arch.cr0 & X86_CR0_PE)) {
+ kvm_inject_gp(ctxt->vcpu, 0);
+ return -1;
+ }
+
+ /* sysexit must be called from CPL 0 */
+ if (kvm_x86_ops->get_cpl(ctxt->vcpu) != 0) {
+ kvm_inject_gp(ctxt->vcpu, 0);
+ return -1;
+ }
+
+ setup_syscalls_segments(ctxt, &cs, &ss);
+
+ if ((c->rex_prefix & 0x8) != 0x0)
+ usermode = X86EMUL_MODE_PROT64;
+ else
+ usermode = X86EMUL_MODE_PROT32;
+
+ cs.dpl = 3;
+ ss.dpl = 3;
+ kvm_x86_ops->get_msr(ctxt->vcpu, MSR_IA32_SYSENTER_CS, &msr_data);
+ switch (usermode) {
+ case X86EMUL_MODE_PROT32:
+ cs.selector = (u16)(msr_data + 16);
+ if ((msr_data & 0xfffc) == 0x0) {
+ kvm_inject_gp(ctxt->vcpu, 0);
+ return -1;
+ }
+ ss.selector = (u16)(msr_data + 24);
+ break;
+ case X86EMUL_MODE_PROT64:
+ cs.selector = (u16)(msr_data + 32);
+ if (msr_data == 0x0) {
+ kvm_inject_gp(ctxt->vcpu, 0);
+ return -1;
+ }
+ ss.selector = cs.selector + 8;
+ cs.db = 0;
+ cs.l = 1;
+ break;
+ }
+ cs.selector |= SELECTOR_RPL_MASK;
+ ss.selector |= SELECTOR_RPL_MASK;
+
+ kvm_x86_ops->set_segment(ctxt->vcpu, &cs, VCPU_SREG_CS);
+ kvm_x86_ops->set_segment(ctxt->vcpu, &ss, VCPU_SREG_SS);
+
+ c->eip = ctxt->vcpu->arch.regs[VCPU_REGS_RDX];
+ c->regs[VCPU_REGS_RSP] = ctxt->vcpu->arch.regs[VCPU_REGS_RCX];
+
+ return 0;
+}
+
int
x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
{
@@ -1970,6 +2203,12 @@ twobyte_insn:
goto cannot_emulate;
}
break;
+ case 0x05: /* syscall */
+ if (emulate_syscall(ctxt) == -1)
+ goto cannot_emulate;
+ else
+ goto writeback;
+ break;
case 0x06:
emulate_clts(ctxt->vcpu);
c->dst.type = OP_NONE;
@@ -2036,6 +2275,18 @@ twobyte_insn:
rc = X86EMUL_CONTINUE;
c->dst.type = OP_NONE;
break;
+ case 0x34: /* sysenter */
+ if (emulate_sysenter(ctxt) == -1)
+ goto cannot_emulate;
+ else
+ goto writeback;
+ break;
+ case 0x35: /* sysexit */
+ if (emulate_sysexit(ctxt) == -1)
+ goto cannot_emulate;
+ else
+ goto writeback;
+ break;
case 0x40 ... 0x4f: /* cmov */
c->dst.val = c->dst.orig_val = c->src.val;
if (!test_cc(c->b, ctxt->eflags))
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-18 19:55:38 +0000