linux-kernel - KVM: x86: expose HINTS_REALTIME ablility to qemu

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Date:   Fri, 13 Aug 2021 17:54:20 +0800
From:   Aili Yao <yaoaili@...gsoft.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>
CC:     <yaoaili126@...il.com>, <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>, <kvm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: KVM: x86: expose HINTS_REALTIME ablility to qemu

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@...gsoft.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