linux-kernel - [PATCH v2] KVM: VMX: drop I/O permission bitmaps

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Message-Id: <1513068261-2019-1-git-send-email-quan.xu0@gmail.com>
Date:   Tue, 12 Dec 2017 16:44:21 +0800
From:   Quan Xu <quan.xu0@...il.com>
To:     kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, rkrcmar@...hat.com,
        jmattson@...gle.com, pbonzini@...hat.com, david@...hat.com,
        Quan Xu <quan.xu0@...il.com>
Subject: [PATCH v2] KVM: VMX: drop I/O permission bitmaps

From: Quan Xu <quan.xu0@...il.com>

Since KVM removes the only I/O port 0x80 bypass on Intel hosts,
clear CPU_BASED_USE_IO_BITMAPS and set CPU_BASED_UNCOND_IO_EXITING
bit. Then these I/O permission bitmaps are not used at all, so
drop I/O permission bitmaps.

Signed-off-by: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Radim Krčmář <rkrcmar@...hat.com>
Signed-off-by: Quan Xu <quan.xu0@...il.com>
---
 arch/x86/kvm/vmx.c |   15 +--------------
 1 files changed, 1 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2fd9a8c..41aaf5e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -943,8 +943,6 @@ static bool nested_vmx_is_page_fault_vmexit(struct vmcs12 *vmcs12,
 static DEFINE_PER_CPU(spinlock_t, blocked_vcpu_on_cpu_lock);
 
 enum {
-	VMX_IO_BITMAP_A,
-	VMX_IO_BITMAP_B,
 	VMX_MSR_BITMAP_LEGACY,
 	VMX_MSR_BITMAP_LONGMODE,
 	VMX_MSR_BITMAP_LEGACY_X2APIC_APICV,
@@ -958,8 +956,6 @@ enum {
 
 static unsigned long *vmx_bitmap[VMX_BITMAP_NR];
 
-#define vmx_io_bitmap_a                      (vmx_bitmap[VMX_IO_BITMAP_A])
-#define vmx_io_bitmap_b                      (vmx_bitmap[VMX_IO_BITMAP_B])
 #define vmx_msr_bitmap_legacy                (vmx_bitmap[VMX_MSR_BITMAP_LEGACY])
 #define vmx_msr_bitmap_longmode              (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE])
 #define vmx_msr_bitmap_legacy_x2apic_apicv   (vmx_bitmap[VMX_MSR_BITMAP_LEGACY_X2APIC_APICV])
@@ -3632,7 +3628,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
 #endif
 	      CPU_BASED_CR3_LOAD_EXITING |
 	      CPU_BASED_CR3_STORE_EXITING |
-	      CPU_BASED_USE_IO_BITMAPS |
+	      CPU_BASED_UNCOND_IO_EXITING |
 	      CPU_BASED_MOV_DR_EXITING |
 	      CPU_BASED_USE_TSC_OFFSETING |
 	      CPU_BASED_INVLPG_EXITING |
@@ -5445,10 +5441,6 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx)
 #endif
 	int i;
 
-	/* I/O */
-	vmcs_write64(IO_BITMAP_A, __pa(vmx_io_bitmap_a));
-	vmcs_write64(IO_BITMAP_B, __pa(vmx_io_bitmap_b));
-
 	if (enable_shadow_vmcs) {
 		vmcs_write64(VMREAD_BITMAP, __pa(vmx_vmread_bitmap));
 		vmcs_write64(VMWRITE_BITMAP, __pa(vmx_vmwrite_bitmap));
@@ -6751,14 +6743,9 @@ static __init int hardware_setup(void)
 			goto out;
 	}
 
-	vmx_io_bitmap_b = (unsigned long *)__get_free_page(GFP_KERNEL);
 	memset(vmx_vmread_bitmap, 0xff, PAGE_SIZE);
 	memset(vmx_vmwrite_bitmap, 0xff, PAGE_SIZE);
 
-	memset(vmx_io_bitmap_a, 0xff, PAGE_SIZE);
-
-	memset(vmx_io_bitmap_b, 0xff, PAGE_SIZE);
-
 	memset(vmx_msr_bitmap_legacy, 0xff, PAGE_SIZE);
 	memset(vmx_msr_bitmap_longmode, 0xff, PAGE_SIZE);
 
-- 
1.7.1