Enable VMX MSR bitmap support.

We use it to avoid VMExits on FS_BASE and GS_BASE MSR accesses.

Signed-off-by: Weidong Han <weidong.han@intel.com>
Signed-off-by: Xin Li <xin.b.li@intel.com>
Signed-off-by: Keir Fraser <keir@xensource.com>

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index d01935de823018c979851f91e4c969fca7ff6502..3a40d69c011f7405db07611bc52cbed38e45e788 100644 (file)
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -59,6 +59,9 @@ struct hvm_function_table hvm_funcs __read_mostly;
 /* I/O permission bitmap is globally shared by all HVM guests. */
 char __attribute__ ((__section__ (".bss.page_aligned")))
     hvm_io_bitmap[3*PAGE_SIZE];
+/* MSR permission bitmap is globally shared by all HVM guests. */
+char __attribute__ ((__section__ (".bss.page_aligned")))
+    hvm_msr_bitmap[PAGE_SIZE];
 
 void hvm_enable(struct hvm_function_table *fns)
 {
@@ -72,6 +75,9 @@ void hvm_enable(struct hvm_function_table *fns)
     memset(hvm_io_bitmap, ~0, sizeof(hvm_io_bitmap));
     clear_bit(0x80, hvm_io_bitmap);
 
+    /* All MSR accesses are intercepted by default. */
+    memset(hvm_msr_bitmap, ~0, sizeof(hvm_msr_bitmap));
+
     hvm_funcs   = *fns;
     hvm_enabled = 1;
 }

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index e7009afb5cc6db10634e8ccb55ed6d6083182352..a8d92dd1cf67ac59f73bb482d17fd005a5d9bf39 100644 (file)
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -61,6 +61,25 @@ static u32 adjust_vmx_controls(u32 ctl_min, u32 ctl_max, u32 msr)
     return ctl;
 }
 
+static void disable_intercept_for_msr(u32 msr)
+{
+    /*
+     * See Intel PRM Vol. 3, 20.6.9 (MSR-Bitmap Address).
+     * We can control MSRs 0x00000000-0x00001fff and 0xc0000000-0xc0001fff.
+     */
+    if ( msr <= 0x1fff )
+    {
+        __clear_bit(msr, hvm_msr_bitmap + 0x000); /* read-low */
+        __clear_bit(msr, hvm_msr_bitmap + 0x400); /* write-low */
+    }
+    else if ( (msr >= 0xc0000000) && (msr <= 0xc0001fff) )
+    {
+        msr &= 0x1fff;
+        __clear_bit(msr, hvm_msr_bitmap + 0x800); /* read-high */
+        __clear_bit(msr, hvm_msr_bitmap + 0xc00); /* write-high */
+    }
+}
+
 void vmx_init_vmcs_config(void)
 {
     u32 vmx_msr_low, vmx_msr_high, min, max;
@@ -82,6 +101,7 @@ void vmx_init_vmcs_config(void)
 #ifdef __x86_64__
     min = max |= CPU_BASED_CR8_LOAD_EXITING | CPU_BASED_CR8_STORE_EXITING;
 #endif
+    max |= CPU_BASED_ACTIVATE_MSR_BITMAP;
     _vmx_cpu_based_exec_control = adjust_vmx_controls(
         min, max, MSR_IA32_VMX_PROCBASED_CTLS_MSR);
 
@@ -105,6 +125,9 @@ void vmx_init_vmcs_config(void)
         vmx_cpu_based_exec_control = _vmx_cpu_based_exec_control;
         vmx_vmexit_control         = _vmx_vmexit_control;
         vmx_vmentry_control        = _vmx_vmentry_control;
+
+        disable_intercept_for_msr(MSR_FS_BASE);
+        disable_intercept_for_msr(MSR_GS_BASE);
     }
     else
     {
@@ -287,6 +310,9 @@ static void construct_vmcs(struct vcpu *v)
     __vmwrite(CPU_BASED_VM_EXEC_CONTROL, vmx_cpu_based_exec_control);
     v->arch.hvm_vcpu.u.vmx.exec_control = vmx_cpu_based_exec_control;
 
+    if ( vmx_cpu_based_exec_control & CPU_BASED_ACTIVATE_MSR_BITMAP )
+        __vmwrite(MSR_BITMAP, virt_to_maddr(hvm_msr_bitmap));
+
     /* I/O access bitmap. */
     __vmwrite(IO_BITMAP_A, virt_to_maddr(hvm_io_bitmap));
     __vmwrite(IO_BITMAP_B, virt_to_maddr(hvm_io_bitmap + PAGE_SIZE));

diff --git a/xen/include/asm-x86/hvm/support.h b/xen/include/asm-x86/hvm/support.h
index 3d7b3a43bbd26b1fcd6d0fb86d53aaf7691215fb..fea8611bf8ab838263d4c629e66affa5ee2f23a0 100644 (file)
--- a/xen/include/asm-x86/hvm/support.h
+++ b/xen/include/asm-x86/hvm/support.h
@@ -215,6 +215,7 @@ int hvm_load(struct domain *d, hvm_domain_context_t *h);
 /* End of save/restore */
 
 extern char hvm_io_bitmap[];
+extern char hvm_msr_bitmap[];
 extern int hvm_enabled;
 
 void hvm_enable(struct hvm_function_table *);

diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h b/xen/include/asm-x86/hvm/vmx/vmcs.h
index 2fa9c333f37872b09910d85bded65cd7ae56af02..077dd619198eede214db23f70da5d17591a4f4a3 100644 (file)
--- a/xen/include/asm-x86/hvm/vmx/vmcs.h
+++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
@@ -109,6 +109,7 @@ extern int vmcs_version;
 #define CPU_BASED_MOV_DR_EXITING        0x00800000
 #define CPU_BASED_UNCOND_IO_EXITING     0x01000000
 #define CPU_BASED_ACTIVATE_IO_BITMAP    0x02000000
+#define CPU_BASED_ACTIVATE_MSR_BITMAP   0x10000000
 #define CPU_BASED_MONITOR_EXITING       0x20000000
 #define CPU_BASED_PAUSE_EXITING         0x40000000
 
@@ -143,6 +144,8 @@ enum vmcs_field {
     IO_BITMAP_A_HIGH                = 0x00002001,
     IO_BITMAP_B                     = 0x00002002,
     IO_BITMAP_B_HIGH                = 0x00002003,
+    MSR_BITMAP                      = 0x00002004,
+    MSR_BITMAP_HIGH                 = 0x00002005,
     VM_EXIT_MSR_STORE_ADDR          = 0x00002006,
     VM_EXIT_MSR_STORE_ADDR_HIGH     = 0x00002007,
     VM_EXIT_MSR_LOAD_ADDR           = 0x00002008,

diff --git a/xen/include/asm-x86/msr.h b/xen/include/asm-x86/msr.h
index 31e2afd8bf6fb005e14efe3890c54e726cff8d6d..bd7f27b6c52388d3c0963222d2f17e9b445c8c94 100644 (file)
--- a/xen/include/asm-x86/msr.h
+++ b/xen/include/asm-x86/msr.h
@@ -126,8 +126,8 @@ static inline void wrmsrl(unsigned int msr, __u64 val)
 #define MSR_LSTAR 0xc0000082           /* long mode SYSCALL target */
 #define MSR_CSTAR 0xc0000083           /* compatibility mode SYSCALL target */
 #define MSR_SYSCALL_MASK 0xc0000084    /* EFLAGS mask for syscall */
-#define MSR_FS_BASE 0xc0000100         /* 64bit GS base */
-#define MSR_GS_BASE 0xc0000101         /* 64bit FS base */
+#define MSR_FS_BASE 0xc0000100         /* 64bit FS base */
+#define MSR_GS_BASE 0xc0000101         /* 64bit GS base */
 #define MSR_SHADOW_GS_BASE  0xc0000102 /* SwapGS GS shadow */ 
 /* EFER bits: */ 
 #define _EFER_SCE 0  /* SYSCALL/SYSRET */