linux-kernel - [PATCH 3.19.y-ckt 32/86] KVM: vmx: fix VPID is 0000H in non-root operation

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Message-Id: <1445981426-19727-33-git-send-email-kamal@canonical.com>
Date:	Tue, 27 Oct 2015 14:29:32 -0700
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Wanpeng Li <wanpeng.li@...mail.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 3.19.y-ckt 32/86] KVM: vmx: fix VPID is 0000H in non-root operation

3.19.8-ckt9 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Wanpeng Li <wanpeng.li@...mail.com>

commit 04bb92e4b4cf06a66889d37b892b78f926faa9d4 upstream.

Reference SDM 28.1:

The current VPID is 0000H in the following situations:
- Outside VMX operation. (This includes operation in system-management
  mode under the default treatment of SMIs and SMM with VMX operation;
  see Section 34.14.)
- In VMX root operation.
- In VMX non-root operation when the “enable VPID” VM-execution control
  is 0.

The VPID should never be 0000H in non-root operation when "enable VPID"
VM-execution control is 1. However, commit 34a1cd60 ("kvm: x86: vmx:
move some vmx setting from vmx_init() to hardware_setup()") remove the
codes which reserve 0000H for VMX root operation.

This patch fix it by again reserving 0000H for VMX root operation.

Fixes: 34a1cd60d17f62c1f077c1478a6c2ca8c3d17af4
Reported-by: Wincy Van <fanwenyi0529@...il.com>
Signed-off-by: Wanpeng Li <wanpeng.li@...mail.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 arch/x86/kvm/vmx.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index bde6bd1..ba2ba0f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5918,6 +5918,8 @@ static __init int hardware_setup(void)
 	memcpy(vmx_msr_bitmap_longmode_x2apic,
 			vmx_msr_bitmap_longmode, PAGE_SIZE);
 
+	set_bit(0, vmx_vpid_bitmap); /* 0 is reserved for host */
+
 	if (enable_apicv) {
 		for (msr = 0x800; msr <= 0x8ff; msr++)
 			vmx_disable_intercept_msr_read_x2apic(msr);
-- 
1.9.1

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