Received-SPF: pass (google.com: domain of linux-kernel+bounces-139963-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
From: Alexandre Chartre <alexandre.chartre@oracle.com>
To: x86@kernel.org, kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, daniel.sneddon@linux.intel.com,
        pawan.kumar.gupta@linux.intel.com, tglx@linutronix.de,
        konrad.wilk@oracle.com, peterz@infradead.org,
        gregkh@linuxfoundation.org, seanjc@google.com,
        andrew.cooper3@citrix.com, dave.hansen@linux.intel.com,
        nik.borisov@suse.com, kpsingh@kernel.org, longman@redhat.com,
        bp@alien8.de, pbonzini@redhat.com, alexandre.chartre@oracle.com
Subject: [PATCH] KVM: x86: Set BHI_NO in guest when host is not affected by BHI
Date: Thu, 11 Apr 2024 09:24:45 +0200
Message-Id: <20240411072445.522731-1-alexandre.chartre@oracle.com>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

When a system is not affected by the BHI bug then KVM should
configure guests with BHI_NO to ensure they won't enable any
BHI mitigation.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
---
 arch/x86/kvm/x86.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 984ea2089efc..f43d3c15a6b7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1678,6 +1678,9 @@ static u64 kvm_get_arch_capabilities(void)
 	if (!boot_cpu_has_bug(X86_BUG_GDS) || gds_ucode_mitigated())
 		data |= ARCH_CAP_GDS_NO;
 
+	if (!boot_cpu_has_bug(X86_BUG_BHI))
+		data |= ARCH_CAP_BHI_NO;
+
 	return data;
 }
 
-- 
2.39.3