Christian Hesse wrote:
> On Tuesday 24 April 2007, Avi Kivity wrote:
>
>> Jeff Chua wrote:
>>
>>> On 4/22/07, Avi Kivity <[EMAIL PROTECTED]> wrote:
>>>
>>>> Significant cpu performance improvements (esp. for 32-bit guests on
>>>> 64-bit hosts), as well as Windows 2000 support (without acpi).
>>>>
>>> Avi,
>>>
>>> Ecountered the following error with kvm-20 (external modules) on
>>> Linux-2.6.21-rc7.
>>>
>>> kvm_run: failed entry, reason 7
>>> kvm_run returned -8
>>>
>>> Runs fine with kvm-19 (external modules).
>>>
>>> Am I missing something?
>>>
>> I'm missing something:
>>
>> - what host cpu?
>>
>> - what host bitness?
>>
>> - what guest OS?
>>
>
> Hi Avi,
>
> same here, so I will answer in place:
>
> Samsung X11 with Intel Core Duo T2300 with Gentoo Linux and Kernel 2.6.21-rc7
> + kvm-20. Guest OS is Win XP.
>
> Additionally I've patched my kernel with cfs v5 now. I thought that could be
> the problem... Jeff, are you running cfs or any non mainline scheduler as
> well?
>
It may be the cpuid strangeness that Rusty saw. Can you try the
attached patch?
--
Do not meddle in the internals of kernels, for they are subtle and quick to
panic.
diff --git a/qemu/qemu-kvm.c b/qemu/qemu-kvm.c
index e00b0f3..46b0b99 100644
--- a/qemu/qemu-kvm.c
+++ b/qemu/qemu-kvm.c
@@ -682,6 +682,49 @@ void kvm_qemu_destroy(void)
kvm_finalize(kvm_context);
}
+static void host_cpuid(uint32_t function, uint32_t *eax, uint32_t *ebx,
+ uint32_t *ecx, uint32_t *edx)
+{
+ uint32_t vec[4];
+
+ vec[0] = function;
+ asm volatile (
+#ifdef __x86_64__
+ "push %0; push %%rsi \n\t"
+ "push %%rax; push %%rbx; push %%rcx; push %%rdx \n\t"
+ "mov 8*5(%%rsp), %%rsi \n\t"
+ "mov (%%rsi), %%eax \n\t"
+ "cpuid \n\t"
+ "mov %%eax, (%%rsi) \n\t"
+ "mov %%ebx, 4(%%rsi) \n\t"
+ "mov %%ecx, 8(%%rsi) \n\t"
+ "mov %%edx, 12(%%rsi) \n\t"
+ "pop %%rdx; pop %%rcx; pop %%rbx; pop %%rax \n\t"
+ "pop %%rsi; pop %0 \n\t"
+#else
+ "push %0; push %%esi \n\t"
+ "push %%eax; push %%ebx; push %%ecx; push %%edx \n\t"
+ "mov 4*5(%%esp), %%esi \n\t"
+ "mov (%%esi), %%eax \n\t"
+ "cpuid \n\t"
+ "mov %%eax, (%%esi) \n\t"
+ "mov %%ebx, 4(%%esi) \n\t"
+ "mov %%ecx, 8(%%esi) \n\t"
+ "mov %%edx, 12(%%esi) \n\t"
+ "pop %%edx; pop %%ecx; pop %%ebx; pop %%eax \n\t"
+ "pop %%esi; pop %0 \n\t"
+#endif
+ : : "rm"(vec) : "memory");
+ if (eax)
+ *eax = vec[0];
+ if (ebx)
+ *ebx = vec[1];
+ if (ecx)
+ *ecx = vec[2];
+ if (edx)
+ *edx = vec[3];
+}
+
static void do_cpuid_ent(struct kvm_cpuid_entry *e, uint32_t function)
{
EAX = function;
@@ -694,17 +737,9 @@ static void do_cpuid_ent(struct kvm_cpuid_entry *e, uint32_t function)
if (function == 1)
e->edx &= ~(1 << 12); /* disable mtrr support */
if (function == 0x80000001) {
- unsigned long h_eax = function, h_edx;
+ uint32_t h_eax, h_edx;
-
- // push/pop hack to workaround gcc 3 register pressure trouble
- asm (
-#ifdef __x86_64__
- "push %%rbx; push %%rcx; cpuid; pop %%rcx; pop %%rbx"
-#else
- "push %%ebx; push %%ecx; cpuid; pop %%ecx; pop %%ebx"
-#endif
- : "+a"(h_eax), "=d"(h_edx));
+ host_cpuid(function, &h_eax, NULL, NULL, &h_edx);
// long mode
if ((h_edx & 0x20000000) == 0)
@@ -722,27 +757,8 @@ static void do_cpuid_ent(struct kvm_cpuid_entry *e, uint32_t function)
// is you use compatibility mode.
if (function == 0) {
uint32_t bcd[3];
- asm (
-#ifdef __x86_64__
- "push %%rax; push %%rbx; push %%rcx; push %%rdx \n\t"
- "mov $0, %%eax \n\t"
- "cpuid \n\t"
- "mov (%%rsp), %%rax \n\t"
- "mov %%ebx, (%%rax) \n\t"
- "mov %%ecx, 4(%%rax) \n\t"
- "mov %%edx, 8(%%rax) \n\t"
- "pop %%rdx; pop %%rcx; pop %%rbx; pop %%rax"
-#else
- "push %%eax; push %%ebx; push %%ecx; push %%edx \n\t"
- "mov $0, %%eax \n\t"
- "cpuid \n\t"
- "mov (%%esp), %%eax \n\t"
- "mov %%ebx, (%%eax) \n\t"
- "mov %%ecx, 4(%%eax) \n\t"
- "mov %%edx, 8(%%eax) \n\t"
- "pop %%edx; pop %%ecx; pop %%ebx; pop %%eax"
-#endif
- : : "d"(bcd) : "memory");
+
+ host_cpuid(0, NULL, &bcd[0], &bcd[1], &bcd[2]);
e->ebx = bcd[0];
e->ecx = bcd[1];
e->edx = bcd[2];
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