--- /dev/null
+From bdb42f5afebe208eae90406959383856ae2caf2b Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Stephan=20B=C3=A4rwolf?= <stephan.baerwolf@tu-ilmenau.de>
+Date: Thu, 12 Jan 2012 16:43:03 +0100
+Subject: KVM: x86: extend "struct x86_emulate_ops" with "get_cpuid"
+
+From: =?UTF-8?q?Stephan=20B=C3=A4rwolf?= <stephan.baerwolf@tu-ilmenau.de>
+
+commit bdb42f5afebe208eae90406959383856ae2caf2b upstream.
+
+In order to be able to proceed checks on CPU-specific properties
+within the emulator, function "get_cpuid" is introduced.
+With "get_cpuid" it is possible to virtually call the guests
+"cpuid"-opcode without changing the VM's context.
+
+[mtosatti: cleanup/beautify code]
+
+Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de>
+Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
+Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/x86/include/asm/kvm_emulate.h | 3 +++
+ arch/x86/kvm/x86.c | 23 +++++++++++++++++++++++
+ 2 files changed, 26 insertions(+)
+
+--- a/arch/x86/include/asm/kvm_emulate.h
++++ b/arch/x86/include/asm/kvm_emulate.h
+@@ -189,6 +189,9 @@ struct x86_emulate_ops {
+ int (*intercept)(struct x86_emulate_ctxt *ctxt,
+ struct x86_instruction_info *info,
+ enum x86_intercept_stage stage);
++
++ bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt,
++ u32 *eax, u32 *ebx, u32 *ecx, u32 *edx);
+ };
+
+ typedef u32 __attribute__((vector_size(16))) sse128_t;
+--- a/arch/x86/kvm/x86.c
++++ b/arch/x86/kvm/x86.c
+@@ -4407,6 +4407,28 @@ static int emulator_intercept(struct x86
+ return kvm_x86_ops->check_intercept(emul_to_vcpu(ctxt), info, stage);
+ }
+
++static bool emulator_get_cpuid(struct x86_emulate_ctxt *ctxt,
++ u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
++{
++ struct kvm_cpuid_entry2 *cpuid = NULL;
++
++ if (eax && ecx)
++ cpuid = kvm_find_cpuid_entry(emul_to_vcpu(ctxt),
++ *eax, *ecx);
++
++ if (cpuid) {
++ *eax = cpuid->eax;
++ *ecx = cpuid->ecx;
++ if (ebx)
++ *ebx = cpuid->ebx;
++ if (edx)
++ *edx = cpuid->edx;
++ return true;
++ }
++
++ return false;
++}
++
+ static struct x86_emulate_ops emulate_ops = {
+ .read_std = kvm_read_guest_virt_system,
+ .write_std = kvm_write_guest_virt_system,
+@@ -4437,6 +4459,7 @@ static struct x86_emulate_ops emulate_op
+ .get_fpu = emulator_get_fpu,
+ .put_fpu = emulator_put_fpu,
+ .intercept = emulator_intercept,
++ .get_cpuid = emulator_get_cpuid,
+ };
+
+ static void cache_all_regs(struct kvm_vcpu *vcpu)
--- /dev/null
+From c2226fc9e87ba3da060e47333657cd6616652b84 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Stephan=20B=C3=A4rwolf?= <stephan.baerwolf@tu-ilmenau.de>
+Date: Thu, 12 Jan 2012 16:43:04 +0100
+Subject: KVM: x86: fix missing checks in syscall emulation
+
+From: =?UTF-8?q?Stephan=20B=C3=A4rwolf?= <stephan.baerwolf@tu-ilmenau.de>
+
+commit c2226fc9e87ba3da060e47333657cd6616652b84 upstream.
+
+On hosts without this patch, 32bit guests will crash (and 64bit guests
+may behave in a wrong way) for example by simply executing following
+nasm-demo-application:
+
+ [bits 32]
+ global _start
+ SECTION .text
+ _start: syscall
+
+(I tested it with winxp and linux - both always crashed)
+
+ Disassembly of section .text:
+
+ 00000000 <_start>:
+ 0: 0f 05 syscall
+
+The reason seems a missing "invalid opcode"-trap (int6) for the
+syscall opcode "0f05", which is not available on Intel CPUs
+within non-longmodes, as also on some AMD CPUs within legacy-mode.
+(depending on CPU vendor, MSR_EFER and cpuid)
+
+Because previous mentioned OSs may not engage corresponding
+syscall target-registers (STAR, LSTAR, CSTAR), they remain
+NULL and (non trapping) syscalls are leading to multiple
+faults and finally crashs.
+
+Depending on the architecture (AMD or Intel) pretended by
+guests, various checks according to vendor's documentation
+are implemented to overcome the current issue and behave
+like the CPUs physical counterparts.
+
+[mtosatti: cleanup/beautify code]
+
+Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de>
+Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
+Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ arch/x86/include/asm/kvm_emulate.h | 13 +++++++++
+ arch/x86/kvm/emulate.c | 51 +++++++++++++++++++++++++++++++++++++
+ 2 files changed, 64 insertions(+)
+
+--- a/arch/x86/include/asm/kvm_emulate.h
++++ b/arch/x86/include/asm/kvm_emulate.h
+@@ -301,6 +301,19 @@ struct x86_emulate_ctxt {
+ #define X86EMUL_MODE_PROT (X86EMUL_MODE_PROT16|X86EMUL_MODE_PROT32| \
+ X86EMUL_MODE_PROT64)
+
++/* CPUID vendors */
++#define X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx 0x68747541
++#define X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx 0x444d4163
++#define X86EMUL_CPUID_VENDOR_AuthenticAMD_edx 0x69746e65
++
++#define X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx 0x69444d41
++#define X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx 0x21726574
++#define X86EMUL_CPUID_VENDOR_AMDisbetterI_edx 0x74656273
++
++#define X86EMUL_CPUID_VENDOR_GenuineIntel_ebx 0x756e6547
++#define X86EMUL_CPUID_VENDOR_GenuineIntel_ecx 0x6c65746e
++#define X86EMUL_CPUID_VENDOR_GenuineIntel_edx 0x49656e69
++
+ enum x86_intercept_stage {
+ X86_ICTP_NONE = 0, /* Allow zero-init to not match anything */
+ X86_ICPT_PRE_EXCEPT,
+--- a/arch/x86/kvm/emulate.c
++++ b/arch/x86/kvm/emulate.c
+@@ -1901,6 +1901,51 @@ setup_syscalls_segments(struct x86_emula
+ ss->p = 1;
+ }
+
++static bool em_syscall_is_enabled(struct x86_emulate_ctxt *ctxt)
++{
++ struct x86_emulate_ops *ops = ctxt->ops;
++ u32 eax, ebx, ecx, edx;
++
++ /*
++ * syscall should always be enabled in longmode - so only become
++ * vendor specific (cpuid) if other modes are active...
++ */
++ if (ctxt->mode == X86EMUL_MODE_PROT64)
++ return true;
++
++ eax = 0x00000000;
++ ecx = 0x00000000;
++ if (ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx)) {
++ /*
++ * Intel ("GenuineIntel")
++ * remark: Intel CPUs only support "syscall" in 64bit
++ * longmode. Also an 64bit guest with a
++ * 32bit compat-app running will #UD !! While this
++ * behaviour can be fixed (by emulating) into AMD
++ * response - CPUs of AMD can't behave like Intel.
++ */
++ if (ebx == X86EMUL_CPUID_VENDOR_GenuineIntel_ebx &&
++ ecx == X86EMUL_CPUID_VENDOR_GenuineIntel_ecx &&
++ edx == X86EMUL_CPUID_VENDOR_GenuineIntel_edx)
++ return false;
++
++ /* AMD ("AuthenticAMD") */
++ if (ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx &&
++ ecx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ecx &&
++ edx == X86EMUL_CPUID_VENDOR_AuthenticAMD_edx)
++ return true;
++
++ /* AMD ("AMDisbetter!") */
++ if (ebx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ebx &&
++ ecx == X86EMUL_CPUID_VENDOR_AMDisbetterI_ecx &&
++ edx == X86EMUL_CPUID_VENDOR_AMDisbetterI_edx)
++ return true;
++ }
++
++ /* default: (not Intel, not AMD), apply Intel's stricter rules... */
++ return false;
++}
++
+ static int
+ emulate_syscall(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
+ {
+@@ -1915,9 +1960,15 @@ emulate_syscall(struct x86_emulate_ctxt
+ ctxt->mode == X86EMUL_MODE_VM86)
+ return emulate_ud(ctxt);
+
++ if (!(em_syscall_is_enabled(ctxt)))
++ return emulate_ud(ctxt);
++
+ ops->get_msr(ctxt, MSR_EFER, &efer);
+ setup_syscalls_segments(ctxt, ops, &cs, &ss);
+
++ if (!(efer & EFER_SCE))
++ return emulate_ud(ctxt);
++
+ ops->get_msr(ctxt, MSR_STAR, &msr_data);
+ msr_data >>= 32;
+ cs_sel = (u16)(msr_data & 0xfffc);
projects / thirdparty / kernel / stable-queue.git / commitdiff
