From 737c60624180a62635fc343c782a622b626cddbe Mon Sep 17 00:00:00 2001
From: Eduardo Habkost <ehabkost@redhat.com>
Date: Fri, 18 Sep 2009 14:11:41 -0300
Subject: [PATCH] Revert "KVM: VMX: Don't intercept MSR_KERNEL_GS_BASE"

RH-Reverts: c607fb3320f2b14ad1ffc0f244558c8790d048c5
Bugzilla-related: 488130

This reverts commit c607fb3320f2b14ad1ffc0f244558c8790d048c5:

    KVM: VMX: Don't intercept MSR_KERNEL_GS_BASE

A backport error caused the following issue when starting guests:

kvm_run: failed entry, reason 7
rax 0000000000000000 rbx 0000000000000000 rcx 0000000000000000 rdx 0000000000000663
rsi 0000000000000000 rdi 0000000000000000 rsp 0000000000000000 rbp 0000000000000000
r8  0000000000000000 r9  0000000000000000 r10 0000000000000000 r11 0000000000000000
r12 0000000000000000 r13 0000000000000000 r14 0000000000000000 r15 0000000000000000
rip 000000000000fff0 rflags 00023002
cs f000 (000f0000/0000ffff p 1 dpl 3 db 0 s 1 type 3 l 0 g 0 avl 0)
ds 0000 (00000000/0000ffff p 1 dpl 3 db 0 s 1 type 3 l 0 g 0 avl 0)
es 0000 (00000000/0000ffff p 1 dpl 3 db 0 s 1 type 3 l 0 g 0 avl 0)
ss 0000 (00000000/0000ffff p 1 dpl 3 db 0 s 1 type 3 l 0 g 0 avl 0)
fs 0000 (00000000/0000ffff p 1 dpl 3 db 0 s 1 type 3 l 0 g 0 avl 0)
gs 0000 (00000000/0000ffff p 1 dpl 3 db 0 s 1 type 3 l 0 g 0 avl 0)
tr 0000 (fffbd000/00002088 p 1 dpl 0 db 0 s 0 type b l 0 g 0 avl 0)
ldt 0000 (00000000/0000ffff p 1 dpl 0 db 0 s 0 type 2 l 0 g 0 avl 0)
gdt 0/ffff
idt 0/ffff
cr0 60000010 cr2 0 cr3 0 cr4 0 cr8 0 efer 0
kvm_run returned -8

A fixed patch will follow.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 arch/x86/kvm/vmx.c |   62 ++++++++++++---------------------------------------
 1 files changed, 15 insertions(+), 47 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 34c0a43..3f1f928 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -112,8 +112,7 @@ static DEFINE_PER_CPU(struct list_head, vcpus_on_cpu);
 
 static struct page *vmx_io_bitmap_a;
 static struct page *vmx_io_bitmap_b;
-static struct page *vmx_msr_bitmap_legacy;
-static struct page *vmx_msr_bitmap_longmode;
+static struct page *vmx_msr_bitmap;
 
 static DECLARE_BITMAP(vmx_vpid_bitmap, VMX_NR_VPIDS);
 static DEFINE_SPINLOCK(vmx_vpid_lock);
@@ -825,7 +824,6 @@ static void move_msr_up(struct vcpu_vmx *vmx, int from, int to)
 static void setup_msrs(struct vcpu_vmx *vmx)
 {
 	int save_nmsrs;
-	struct page *msr_bitmap;
 
 	vmx_load_host_state(vmx);
 	save_nmsrs = 0;
@@ -861,15 +859,6 @@ static void setup_msrs(struct vcpu_vmx *vmx)
 		__find_msr_index(vmx, MSR_KERNEL_GS_BASE);
 #endif
 	vmx->msr_offset_efer = __find_msr_index(vmx, MSR_EFER);
-
-	if (cpu_has_vmx_msr_bitmap()) {
-		if (is_long_mode(&vmx->vcpu))
-			msr_bitmap = vmx_msr_bitmap_longmode;
-		else
-			msr_bitmap = vmx_msr_bitmap_legacy;
-
-		vmcs_write64(MSR_BITMAP, __pa(msr_bitmap));
-	}
 }
 
 /*
@@ -2104,7 +2093,7 @@ static void allocate_vpid(struct vcpu_vmx *vmx)
 	spin_unlock(&vmx_vpid_lock);
 }
 
-static void __vmx_disable_intercept_for_msr(struct page *msr_bitmap, u32 msr)
+static void vmx_disable_intercept_for_msr(struct page *msr_bitmap, u32 msr)
 {
 	void *va;
 
@@ -2128,13 +2117,6 @@ static void __vmx_disable_intercept_for_msr(struct page *msr_bitmap, u32 msr)
 	kunmap(msr_bitmap);
 }
 
-static void vmx_disable_intercept_for_msr(u32 msr, bool longmode_only)
-{
-	if (!longmode_only)
-		__vmx_disable_intercept_for_msr(vmx_msr_bitmap_legacy, msr);
-	__vmx_disable_intercept_for_msr(vmx_msr_bitmap_longmode, msr);
-}
-
 /*
  * Sets up the vmcs for emulated real mode.
  */
@@ -2154,7 +2136,7 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
 	vmcs_write64(IO_BITMAP_B, page_to_phys(vmx_io_bitmap_b));
 
 	if (cpu_has_vmx_msr_bitmap())
-		vmcs_write64(MSR_BITMAP, page_to_phys(vmx_msr_bitmap_legacy));
+		vmcs_write64(MSR_BITMAP, page_to_phys(vmx_msr_bitmap));
 
 	vmcs_write64(VMCS_LINK_POINTER, -1ull); /* 22.3.1.5 */
 
@@ -3684,18 +3666,12 @@ static int __init vmx_init(void)
 		goto out;
 	}
 
-	vmx_msr_bitmap_legacy = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
-	if (!vmx_msr_bitmap_legacy) {
+	vmx_msr_bitmap = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
+	if (!vmx_msr_bitmap) {
 		r = -ENOMEM;
 		goto out1;
 	}
 
-	vmx_msr_bitmap_longmode = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
-	if (!vmx_msr_bitmap_longmode) {
-		r = -ENOMEM;
-		goto out2;
-	}
-
 	/*
 	 * Allow direct access to the PC debug port (it is often used for I/O
 	 * delays, but the vmexits simply slow things down).
@@ -3709,26 +3685,21 @@ static int __init vmx_init(void)
 	memset(va, 0xff, PAGE_SIZE);
 	kunmap(vmx_io_bitmap_b);
 
-	va = kmap(vmx_msr_bitmap_legacy);
+	va = kmap(vmx_msr_bitmap);
 	memset(va, 0xff, PAGE_SIZE);
-	kunmap(vmx_msr_bitmap_legacy);
-
-	va = kmap(vmx_msr_bitmap_longmode);
-	memset(va, 0xff, PAGE_SIZE);
-	kunmap(vmx_msr_bitmap_longmode);
+	kunmap(vmx_msr_bitmap);
 
 	set_bit(0, vmx_vpid_bitmap); /* 0 is reserved for host */
 
 	r = kvm_init(&vmx_x86_ops, sizeof(struct vcpu_vmx), THIS_MODULE);
 	if (r)
-		goto out3;
+		goto out2;
 
-	vmx_disable_intercept_for_msr(MSR_FS_BASE, false);
-	vmx_disable_intercept_for_msr(MSR_GS_BASE, false);
-	vmx_disable_intercept_for_msr(MSR_KERNEL_GS_BASE, true);
-	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_CS, false);
-	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_ESP, false);
-	vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
+	vmx_disable_intercept_for_msr(vmx_msr_bitmap, MSR_FS_BASE);
+	vmx_disable_intercept_for_msr(vmx_msr_bitmap, MSR_GS_BASE);
+	vmx_disable_intercept_for_msr(vmx_msr_bitmap, MSR_IA32_SYSENTER_CS);
+	vmx_disable_intercept_for_msr(vmx_msr_bitmap, MSR_IA32_SYSENTER_ESP);
+	vmx_disable_intercept_for_msr(vmx_msr_bitmap, MSR_IA32_SYSENTER_EIP);
 
 	if (vm_need_ept()) {
 		bypass_guest_pf = 0;
@@ -3748,10 +3719,8 @@ static int __init vmx_init(void)
 
 	return 0;
 
-out3:
-	__free_page(vmx_msr_bitmap_longmode);
 out2:
-	__free_page(vmx_msr_bitmap_legacy);
+	__free_page(vmx_msr_bitmap);
 out1:
 	__free_page(vmx_io_bitmap_b);
 out:
@@ -3761,8 +3730,7 @@ out:
 
 static void __exit vmx_exit(void)
 {
-	__free_page(vmx_msr_bitmap_legacy);
-	__free_page(vmx_msr_bitmap_longmode);
+	__free_page(vmx_msr_bitmap);
 	__free_page(vmx_io_bitmap_b);
 	__free_page(vmx_io_bitmap_a);
 
-- 
1.6.3.rc4.29.g8146