linux-kernel - [PATCH 5.9 569/757] KVM: x86: emulating RDPID failure shall return #UD rather than #GP

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Date:   Tue, 27 Oct 2020 14:53:39 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Robert Hoo <robert.hu@...ux.intel.com>,
        Jim Mattson <jmattson@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.9 569/757] KVM: x86: emulating RDPID failure shall return #UD rather than #GP

From: Robert Hoo <robert.hu@...ux.intel.com>

[ Upstream commit a9e2e0ae686094571378c72d8146b5a1a92d0652 ]

Per Intel's SDM, RDPID takes a #UD if it is unsupported, which is more or
less what KVM is emulating when MSR_TSC_AUX is not available.  In fact,
there are no scenarios in which RDPID is supposed to #GP.

Fixes: fb6d4d340e ("KVM: x86: emulate RDPID")
Signed-off-by: Robert Hoo <robert.hu@...ux.intel.com>
Message-Id: <1598581422-76264-1-git-send-email-robert.hu@...ux.intel.com>
Reviewed-by: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/kvm/emulate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 2f6510de6b0c0..85111cd0adcd0 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -3606,7 +3606,7 @@ static int em_rdpid(struct x86_emulate_ctxt *ctxt)
 	u64 tsc_aux = 0;
 
 	if (ctxt->ops->get_msr(ctxt, MSR_TSC_AUX, &tsc_aux))
-		return emulate_gp(ctxt, 0);
+		return emulate_ud(ctxt);
 	ctxt->dst.val = tsc_aux;
 	return X86EMUL_CONTINUE;
 }
-- 
2.25.1