On Thu, 24 Apr 2008 11:05:39 -0500
Anthony Liguori <[EMAIL PROTECTED]> wrote:
> The first stage is to detect vmentry failures and run x86_emulate() for
> a single instruction. If you look at the mailing list, you'll see
> patches from myself and Guillaume. This should be enough to allow most
> Ubuntu installer CDs to work under KVM.
Howdy,
Here is the last patch I have. It can detects a vmentry failure and it
emulates one instruction. I added the emulation of several instructions
like "ljmp", "mov Sreg, reg", "mov reg, Sreg"... The problem I'm
working on is that once I entered in emulation of real mode I do not
manage to recover a VMX friendly state (in my case cs.rpl ==
ss.rpl). So I emulate more and more instructions.
I added a trace to see instructions that are emulated (emulation of
0xa8 is in progress so it currently fails):
[60108.040894] emulation at (46e53) rip 6e13: ea 18 6e 18
[60108.072108] emulation at (46e58) rip 6e18: 66 b8 20 00
[60108.103997] emulation at (46e5c) rip 6e1c: 8e d8 8c d0
[60108.148114] emulation at (46e5e) rip 6e1e: 8c d0 81 e4
[60108.180117] emulation at (46e60) rip 6e20: 81 e4 ff ff
[60108.212008] emulation at (46e66) rip 6e26: c1 e0 04 01
[60108.244926] emulation at (46e69) rip 6e29: 01 c4 66 b8
[60108.272948] emulation at (46e6b) rip 6e2b: 66 b8 08 00
[60108.304953] emulation at (46e6f) rip 6e2f: 8e d0 8e c0
[60108.348973] emulation at (46e71) rip 6e31: 8e c0 8e e0
[60108.396965] emulation at (46e73) rip 6e33: 8e e0 8e e8
[60108.445002] emulation at (46e75) rip 6e35: 8e e8 58 66
[60108.489021] emulation at (46e77) rip 6e37: 58 66 9d 66
[60108.521028] emulation at (46e78) rip 6e38: 66 9d 66 c3
[60108.552979] emulation at (46e7a) rip 6e3a: 66 c3 66 9c
[60108.581048] emulation at (40e2a) rip dea: be 29 0a 00
[60108.613033] emulation at (40e2f) rip def: e8 41 12 00
[60108.644970] emulation at (42075) rip 2035: c6 05 84 07
[60108.673038] emulation at (4207c) rip 203c: e8 18 01 00
[60108.705039] emulation at (42199) rip 2159: 31 c0 80 3d
[60108.736998] emulation at (4219b) rip 215b: 80 3d 86 07
[60108.765041] emulation at (421a2) rip 2162: 74 01 26 ac
[60108.797044] emulation at (421a5) rip 2165: ac c3 80 3d
[60108.829033] emulation at (421a6) rip 2166: c3 80 3d 86
[60108.857068] emulation at (42081) rip 2041: 09 c0 0f 84
[60108.889053] emulation at (42083) rip 2043: 0f 84 0f 01
[60108.921054] emulation at (42198) rip 2158: c3 31 c0 80
[60108.949076] emulation at (40e34) rip df4: 26 66 ff 35
[60108.981077] emulation at (40e3c) rip dfc: 66 8f 05 d0
[60109.013011] emulation at (40e43) rip e03: a1 b4 00 00
[60109.041079] emulation at (40e48) rip e08: 26 8a 40 03
[60109.073039] emulation at (40e4c) rip e0c: a8 01 74 4c
[60109.101078] emulation failed (vmentry failure) rip e0c a8 01 74 4c
So as we can see the first emulated instruction is the ljump and after
we emulate gfxboot loader instruction. I suspect a problem with an
update of SS segment or something like that in instructions that I
emulate.
I paste the patch. Don't worry about the last modification of the two
header files it's not related to real mode emulation.
Regards,
Guillaume
---
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8e5d664..2c4c14d 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1183,7 +1183,9 @@ static void enter_pmode(struct kvm_vcpu *vcpu)
fix_pmode_dataseg(VCPU_SREG_GS, &vcpu->arch.rmode.gs);
fix_pmode_dataseg(VCPU_SREG_FS, &vcpu->arch.rmode.fs);
+#if 0
vmcs_write16(GUEST_SS_SELECTOR, 0);
+#endif
vmcs_write32(GUEST_SS_AR_BYTES, 0x93);
vmcs_write16(GUEST_CS_SELECTOR,
@@ -2323,6 +2325,53 @@ static int handle_task_switch(struct kvm_vcpu *vcpu,
struct kvm_run *kvm_run)
return kvm_task_switch(vcpu, tss_selector, reason);
}
+static int handle_vmentry_failure(struct kvm_vcpu *vcpu,
+ struct kvm_run *kvm_run, u32 failure_reason)
+{
+ u16 ss, cs;
+ u8 opcodes[4];
+ unsigned long rip = vcpu->arch.rip;
+ unsigned long rip_linear;
+
+ ss = vmcs_read16(GUEST_SS_SELECTOR);
+ cs = vmcs_read16(GUEST_CS_SELECTOR);
+
+ if ((ss & 0x03) != (cs & 0x03)) {
+ int err;
+
+#if 0
+ printk(KERN_INFO "vmentry failure because ss.cpl != cs.cpl\n");
+#endif
+ rip_linear = rip + vmx_get_segment_base(vcpu, VCPU_SREG_CS);
+ emulator_read_std(rip_linear, (void *)opcodes, 4, vcpu);
+ printk(KERN_INFO "emulation at (%lx) rip %lx: %02x %02x %02x
%02x\n",
+ rip_linear,
+ rip, opcodes[0], opcodes[1], opcodes[2],
opcodes[3]);
+ err = emulate_instruction(vcpu, kvm_run, 0, 0, 0);
+ switch (err) {
+ case EMULATE_DONE:
+#if 0
+ printk(KERN_INFO "successfully emulated instruction\n");
+#endif
+ return 1;
+ case EMULATE_DO_MMIO:
+ printk(KERN_INFO "mmio?\n");
+ return 0;
+#if 0
+ case EMULATE_FAIL:
+#endif
+ default:
+ kvm_report_emulation_failure(vcpu, "vmentry failure");
+ break;
+ }
+ }
+
+ kvm_run->exit_reason = KVM_EXIT_UNKNOWN;
+ kvm_run->hw.hardware_exit_reason = failure_reason;
+
+ return 0;
+}
+
/*
* The exit handlers return 1 if the exit was handled fully and guest execution
* may resume. Otherwise they set the kvm_run parameter to indicate what needs
@@ -2375,6 +2424,12 @@ static int kvm_handle_exit(struct kvm_run *kvm_run,
struct kvm_vcpu *vcpu)
exit_reason != EXIT_REASON_EXCEPTION_NMI)
printk(KERN_WARNING "%s: unexpected, valid vectoring info and "
"exit reason is 0x%x\n", __func__, exit_reason);
+
+ if ((exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY)) {
+ exit_reason &= ~VMX_EXIT_REASONS_FAILED_VMENTRY;
+ return handle_vmentry_failure(vcpu, kvm_run, exit_reason);
+ }
+
if (exit_reason < kvm_vmx_max_exit_handlers
&& kvm_vmx_exit_handlers[exit_reason])
return kvm_vmx_exit_handlers[exit_reason](vcpu, kvm_run);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0ce5563..f394efd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3267,8 +3267,8 @@ static int load_segment_descriptor_to_kvm_desct(struct
kvm_vcpu *vcpu,
return 0;
}
-static int load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
- int type_bits, int seg)
+int load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
+ int type_bits, int seg)
{
struct kvm_segment kvm_seg;
diff --git a/arch/x86/kvm/x86_emulate.c b/arch/x86/kvm/x86_emulate.c
index 2ca0838..287811c 100644
--- a/arch/x86/kvm/x86_emulate.c
+++ b/arch/x86/kvm/x86_emulate.c
@@ -138,7 +138,8 @@ static u16 opcode_table[256] = {
/* 0x88 - 0x8F */
ByteOp | DstMem | SrcReg | ModRM | Mov, DstMem | SrcReg | ModRM | Mov,
ByteOp | DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
- 0, ModRM | DstReg, 0, Group | Group1A,
+ DstMem | SrcReg | ModRM | Mov, ModRM | DstReg, DstReg |SrcMem |ModRM |
Mov,
+ Group | Group1A,
/* 0x90 - 0x9F */
0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, ImplicitOps | Stack, ImplicitOps | Stack, 0, 0,
@@ -148,11 +149,16 @@ static u16 opcode_table[256] = {
ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
ByteOp | ImplicitOps | String, ImplicitOps | String,
/* 0xA8 - 0xAF */
- 0, 0, ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
+ 0, 0, ByteOp | ImplicitOps | Mov | String,
+ ImplicitOps | Mov | String,
ByteOp | ImplicitOps | Mov | String, ImplicitOps | Mov | String,
ByteOp | ImplicitOps | String, ImplicitOps | String,
- /* 0xB0 - 0xBF */
- 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ /* 0xB0 - 0xB7 */
+ Mov | SrcImmByte, Mov | SrcImmByte, Mov | SrcImmByte, Mov | SrcImmByte,
+ Mov | SrcImmByte, Mov | SrcImmByte, Mov | SrcImmByte, Mov | SrcImmByte,
+ /* 0xB8 - 0xBF */
+ Mov | SrcImm, Mov | SrcImm, Mov | SrcImm, Mov | SrcImm,
+ Mov | SrcImm, Mov | SrcImm, Mov | SrcImm, Mov | SrcImm,
/* 0xC0 - 0xC7 */
ByteOp | DstMem | SrcImm | ModRM, DstMem | SrcImmByte | ModRM,
0, ImplicitOps | Stack, 0, 0,
@@ -168,7 +174,7 @@ static u16 opcode_table[256] = {
/* 0xE0 - 0xE7 */
0, 0, 0, 0, 0, 0, 0, 0,
/* 0xE8 - 0xEF */
- ImplicitOps | Stack, SrcImm|ImplicitOps, 0, SrcImmByte|ImplicitOps,
+ ImplicitOps | Stack, SrcImm|ImplicitOps, ImplicitOps,
SrcImmByte|ImplicitOps,
0, 0, 0, 0,
/* 0xF0 - 0xF7 */
0, 0, 0, 0,
@@ -215,7 +221,7 @@ static u16 twobyte_table[256] = {
/* 0xA0 - 0xA7 */
0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0,
/* 0xA8 - 0xAF */
- 0, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0,
+ ImplicitOps, 0, 0, DstMem | SrcReg | ModRM | BitOp, 0, 0, 0, 0,
/* 0xB0 - 0xB7 */
ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM, 0,
DstMem | SrcReg | ModRM | BitOp,
@@ -680,7 +686,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
c->modrm_val = *(unsigned long *)
decode_register(c->modrm_rm, c->regs, c->d & ByteOp);
return rc;
- }
+ }
if (c->ad_bytes == 2) {
unsigned bx = c->regs[VCPU_REGS_RBX];
@@ -1483,6 +1489,9 @@ special_insn:
goto cmp;
}
break;
+ case 0xa8: /* test imm,%%eax */
+ c->dst.ptr = &c->regs[VCPU_REGS_RAX];
+ c->dst.val = c->regs[VCPU_REGS_RAX];
case 0x84 ... 0x85:
emulate_2op_SrcV("test", c->src, c->dst, ctxt->eflags);
break;
@@ -1511,9 +1520,95 @@ special_insn:
break;
case 0x88 ... 0x8b: /* mov */
goto mov;
+ case 0x8c: { /* mov Sreg, r/m */
+ struct kvm_save_segment *segreg;
+
+ if (c->modrm_mod == 0x3)
+ c->src.val = c->modrm_val;
+
+ switch ( c->modrm_reg ) {
+ case 0:
+ segreg = &ctxt->vcpu->arch.rmode.es;
+ break;
+ case 1:
+ segreg = &ctxt->vcpu->arch.rmode.cs;
+ break;
+ case 2:
+ segreg = &ctxt->vcpu->arch.rmode.ss;
+ break;
+ case 3:
+ segreg = &ctxt->vcpu->arch.rmode.ds;
+ break;
+ case 4:
+ segreg = &ctxt->vcpu->arch.rmode.fs;
+ break;
+ case 5:
+ segreg = &ctxt->vcpu->arch.rmode.gs;
+ break;
+ default:
+ printk(KERN_INFO "Invalid segreg in modrm byte
0x%02x\n",
+ c->modrm);
+ goto cannot_emulate;
+ }
+ c->dst.val = segreg->selector;
+ if (c->dst.type == OP_MEM)
+ c->dst.bytes = 2;
+
+ break;
+ }
case 0x8d: /* lea r16/r32, m */
c->dst.val = c->modrm_ea;
break;
+ case 0x8e: { /* mov seg, r/m16 */
+ struct kvm_save_segment *segreg;
+ int ar_type;
+
+ if (c->modrm_mod == 0x3)
+ c->src.val = c->modrm_val;
+
+ switch ( c->modrm_reg ) {
+ case 0:
+ segreg = &ctxt->vcpu->arch.rmode.es;
+ ar_type = 0x3;
+ printk(KERN_INFO "es_base = %lx\n", c->src.val * 0x10);
+ break;
+ case 1:
+ segreg = &ctxt->vcpu->arch.rmode.cs;
+ ar_type = 0xb;
+ printk(KERN_INFO "cs_base = %lx\n", c->src.val * 0x10);
+ break;
+ case 2:
+ segreg = &ctxt->vcpu->arch.rmode.ss;
+ ar_type = 0x3;
+ printk(KERN_INFO "ss_base = %lx\n", c->src.val * 0x10);
+ break;
+ case 3:
+ segreg = &ctxt->vcpu->arch.rmode.ds;
+ ar_type = 0x3;
+ printk(KERN_INFO "ds_base = %lx\n", c->src.val * 0x10);
+ break;
+ case 4:
+ segreg = &ctxt->vcpu->arch.rmode.fs;
+ ar_type = 0x3;
+ printk(KERN_INFO "fs_base = %lx\n", c->src.val * 0x10);
+ break;
+ case 5:
+ segreg = &ctxt->vcpu->arch.rmode.gs;
+ ar_type = 0x3;
+ printk(KERN_INFO "gs_base = %lx\n", c->src.val * 0x10);
+ break;
+ default:
+ printk(KERN_INFO "Invalid segreg in modrm byte
0x%02x\n", c->modrm);
+ goto cannot_emulate;
+ }
+ segreg->selector = c->src.val;
+ segreg->base = (u64) c->src.val << 4;
+ segreg->limit = 0xffff;
+ segreg->ar = ar_type;
+
+ c->dst.type = OP_NONE; /* Disable writeback. */
+ break;
+ }
case 0x8f: /* pop (sole member of Grp1a) */
rc = emulate_grp1a(ctxt, ops);
if (rc != 0)
@@ -1619,6 +1714,23 @@ special_insn:
case 0xae ... 0xaf: /* scas */
DPRINTF("Urk! I don't handle SCAS.\n");
goto cannot_emulate;
+ case 0xb0 ... 0xb3: /* mov rl, imm8 */
+ c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX + (c->b &
0x3)];
+ c->dst.val = c->src.val;
+ c->dst.type = OP_REG;
+ c->dst.bytes = 1;
+ break;
+ case 0xb4 ... 0xb7: /* mov rh, imm8 */
+ c->dst.ptr = ((void *)&c->regs[VCPU_REGS_RAX + (c->b & 0x3)] +
1);
+ c->dst.val = c->src.val;
+ c->dst.type = OP_REG;
+ c->dst.bytes = 1;
+ break;
+ case 0xb8 ... 0xbf: /* mov r, imm */
+ c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX + (c->b &
0x7)];
+ c->dst.val = c->src.val;
+ c->dst.type = OP_REG;
+ break;
case 0xc0 ... 0xc1:
emulate_grp2(ctxt);
break;
@@ -1661,6 +1773,31 @@ special_insn:
jmp_rel(c, c->src.val);
c->dst.type = OP_NONE; /* Disable writeback. */
break;
+ case 0xea: /* jmp (far, absolute) */ {
+ uint32_t eip;
+ uint16_t sel;
+
+ switch (c->op_bytes) {
+ case 2:
+ eip = insn_fetch(u16, 2, c->eip);
+ eip = eip & 0x0000FFFF; /* clear upper 16 bits */
+ break;
+ case 4:
+ eip = insn_fetch(u32, 4, c->eip);
+ break;
+ default:
+ DPRINTF("Jmp far: Invalid op_bytes\n");
+ goto cannot_emulate;
+ }
+ sel = insn_fetch(u16, 2, c->eip);
+ if (load_segment_descriptor(ctxt->vcpu, sel, 9, VCPU_SREG_CS) <
0) {
+ DPRINTF("Jmp far: Cannot load CS segment descriptor\n");
+ goto cannot_emulate;
+ }
+
+ c->eip = eip;
+ break;
+ }
case 0xf4: /* hlt */
ctxt->vcpu->arch.halt_request = 1;
goto done;
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index 9d963cd..24c8bf9 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -271,7 +271,7 @@ struct kvm_vcpu_arch {
unsigned long base;
u32 limit;
u32 ar;
- } tr, es, ds, fs, gs;
+ } tr, cs, es, ds, fs, gs, ss;
} rmode;
int halt_request; /* real mode on Intel only */
@@ -488,6 +488,8 @@ int emulator_get_dr(struct x86_emulate_ctxt *ctxt, int dr,
int emulator_set_dr(struct x86_emulate_ctxt *ctxt, int dr,
unsigned long value);
+int load_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector,
+ int type_bits, int seg);
int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason);
void kvm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
diff --git a/include/asm-x86/posix_types.h b/include/asm-x86/posix_types.h
index fe312a5..0c8329e 100644
--- a/include/asm-x86/posix_types.h
+++ b/include/asm-x86/posix_types.h
@@ -1,7 +1,13 @@
#ifdef __KERNEL__
-# if defined(CONFIG_X86_32) || defined(__i386__)
+# ifdef CONFIG_X86_32
# include "posix_types_32.h"
# else
# include "posix_types_64.h"
-# endif
+# endif
+#else
+# ifdef __i386__
+# include "posix_types_32.h"
+# else
+# include "posix_types_64.h"
+# endif
#endif
diff --git a/include/asm-x86/unistd.h b/include/asm-x86/unistd.h
index effc7ad..1dea24a 100644
--- a/include/asm-x86/unistd.h
+++ b/include/asm-x86/unistd.h
@@ -1,7 +1,13 @@
#ifdef __KERNEL__
-# if defined(CONFIG_X86_32) || defined(__i386__)
+# ifdef CONFIG_X86_32
# include "unistd_32.h"
# else
# include "unistd_64.h"
-# endif
+# endif
+#else
+# ifdef __i386__
+# include "unistd_32.h"
+# else
+# include "unistd_64.h"
+# endif
#endif
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