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From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] Fix SSBD not being exposed to guests. (v1)
Date: Mon, 21 May 2018 17:54:48 -0400	[thread overview]
Message-ID: <20180521215449.26423-1-konrad.wilk@oracle.com> (raw)

Hi,

Without this patch, when launching QEMU with -cpu +ssbd I ended up
with a warning seeing that the CPU does not support - which in fact it does.

The issue was the X86_FEATURE_ -  the kvm_cpuid_7_0_edx_x86_features
had bit 17 set (X86_FEATURE_SSBD), while the right bit should have been
bit 31 ( X86_FEATURE_SPEC_CTRL_SSBD). That meant the masking:

	entry->edx &= kvm_cpuid_7_0_edx_x86_features;

would nicely clear the SSBD bit.

This fixes:
Fixes: 52817587e706 ("x86/cpufeatures: Disentangle SSBD enumeration")

 arch/x86/kvm/cpuid.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Konrad Rzeszutek Wilk (1):
      KVM: VMX: Expose SSBD properly to guests.

             reply	other threads:[~2018-05-21 21:59 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-21 21:54 Konrad Rzeszutek Wilk [this message]
2018-05-21 21:54 ` [PATCH] KVM: VMX: Expose SSBD properly to guests Konrad Rzeszutek Wilk
2018-05-22 23:50   ` Ben Hutchings
2018-06-07 13:14     ` Thomas Voegtle
2018-05-23  9:00   ` [tip:x86/pti] KVM/VMX: " tip-bot for Konrad Rzeszutek Wilk

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