linux-kernel - [PATCH] KVM: vmx: fix VPID is 0000H in non-root operation

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Message-ID: <BLU436-SMTP979E5F0855A14EAB12C4A5805B0@phx.gbl>
Date:	Wed, 16 Sep 2015 19:31:11 +0800
From:	Wanpeng Li <wanpeng.li@...mail.com>
To:	Paolo Bonzini <pbonzini@...hat.com>
CC:	Jan Kiszka <jan.kiszka@...mens.com>, Bandan Das <bsd@...hat.com>,
	Wincy Van <fanwenyi0529@...il.com>, kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org, Wanpeng Li <wanpeng.li@...mail.com>
Subject: [PATCH] KVM: vmx: fix VPID is 0000H in non-root operation

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 reintroducing reserve 0000H for VMX root operation.

Reported-by: Wincy Van <fanwenyi0529@...il.com>
Signed-off-by: Wanpeng Li <wanpeng.li@...mail.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 9ff6a3f..a63b9ca 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6056,6 +6056,8 @@ 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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