* KVM: x86: expose HINTS_REALTIME ablility to qemu
@ 2021-08-13 9:54 Aili Yao
2021-08-16 6:10 ` Aili Yao
0 siblings, 1 reply; 2+ messages in thread
From: Aili Yao @ 2021-08-13 9:54 UTC (permalink / raw)
To: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel, Thomas Gleixner, Ingo Molnar,
Borislav Petkov
Cc: yaoaili126, x86, H. Peter Anvin, kvm, linux-kernel
When I do a test that try to enable hint-dedicated for one VM, but qemu
says "warning: host doesn't support requested feature:
CPUID.40000001H:EDX.kvm-hint-dedicated [bit 0]".
It seems the kernel hasn't expose this ability even when supporting it;
So expose it.
Signed-off-by: Aili Yao <yaoaili@kingsoft.com>
---
arch/x86/kvm/cpuid.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 739be5da3bca..2153014742d7 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -917,7 +917,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
entry->ebx = 0;
entry->ecx = 0;
- entry->edx = 0;
+ entry->edx = (1 << KVM_HINTS_REALTIME);
break;
case 0x80000000:
entry->eax = min(entry->eax, 0x8000001f);
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: KVM: x86: expose HINTS_REALTIME ablility to qemu
2021-08-13 9:54 KVM: x86: expose HINTS_REALTIME ablility to qemu Aili Yao
@ 2021-08-16 6:10 ` Aili Yao
0 siblings, 0 replies; 2+ messages in thread
From: Aili Yao @ 2021-08-16 6:10 UTC (permalink / raw)
To: Paolo Bonzini, Sean Christopherson, Vitaly Kuznetsov, Wanpeng Li,
Jim Mattson, Joerg Roedel, Thomas Gleixner, Ingo Molnar,
Borislav Petkov
Cc: yaoaili126, x86, H. Peter Anvin, kvm, linux-kernel
On Fri, 13 Aug 2021 17:54:20 +0800
Aili Yao <yaoaili@kingsoft.com> wrote:
> When I do a test that try to enable hint-dedicated for one VM, but qemu
> says "warning: host doesn't support requested feature:
> CPUID.40000001H:EDX.kvm-hint-dedicated [bit 0]".
>
> It seems the kernel hasn't expose this ability even when supporting it;
> So expose it.
Sorry, I check it again:
Ihe issue I met is because of my qemu's mis-backport,
In qemu, kvm_arch_get_supported_cpuid() will set the feature bit:
if (function == KVM_CPUID_FEATURES && reg == R_EDX) {
ret |= KVM_HINTS_DEDICATED;
found = 1;
}
But I have mis-ported the KVM_HINTS_DEDICATED and KVM_HINTS_REALTIME macro; And it lead to
the error I met;
And it's right that kernel don't expose this ability!
Sorry again!
^ permalink raw reply [flat|nested] 2+ messages in thread
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