Skip to content

Commit

Permalink
KVM: VMX: Improve the method of writing vmcs control
Browse files Browse the repository at this point in the history 
Put cpu feature detecting part in hardware_setup, and stored the vmcs
condition in global variable for further check.

[glommer: fix for some i386-only machines not supporting CR8 load/store
 exiting]

Signed-off-by: Sheng Yang <sheng.yang@intel.com>
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
  • Loading branch information
Yang, Sheng authored and Avi Kivity committed Oct 13, 2007
1 parent fb3f0f5 commit 1c3d14f
Showing 1 changed file with 102 additions and 45 deletions.
147 changes: 102 additions & 45 deletions drivers/kvm/vmx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -71,18 +71,17 @@ static DEFINE_PER_CPU(struct vmcs *, current_vmcs);
static struct page *vmx_io_bitmap_a;
static struct page *vmx_io_bitmap_b;

#ifdef CONFIG_X86_64
#define HOST_IS_64 1
#else
#define HOST_IS_64 0
#endif
#define EFER_SAVE_RESTORE_BITS ((u64)EFER_SCE)

static struct vmcs_descriptor {
static struct vmcs_config {
int size;
int order;
u32 revision_id;
} vmcs_descriptor;
u32 pin_based_exec_ctrl;
u32 cpu_based_exec_ctrl;
u32 vmexit_ctrl;
u32 vmentry_ctrl;
} vmcs_config;

#define VMX_SEGMENT_FIELD(seg) \
[VCPU_SREG_##seg] = { \
Expand Down Expand Up @@ -839,14 +838,93 @@ static void hardware_disable(void *garbage)
asm volatile (ASM_VMX_VMXOFF : : : "cc");
}

static __init void setup_vmcs_descriptor(void)
static __init int adjust_vmx_controls(u32 ctl_min, u32 ctl_opt,
u32 msr, u32* result)
{
u32 vmx_msr_low, vmx_msr_high;
u32 ctl = ctl_min | ctl_opt;

rdmsr(msr, vmx_msr_low, vmx_msr_high);

ctl &= vmx_msr_high; /* bit == 0 in high word ==> must be zero */
ctl |= vmx_msr_low; /* bit == 1 in low word ==> must be one */

/* Ensure minimum (required) set of control bits are supported. */
if (ctl_min & ~ctl)
return -1;

*result = ctl;
return 0;
}

static __init int setup_vmcs_config(void)
{
u32 vmx_msr_low, vmx_msr_high;
u32 min, opt;
u32 _pin_based_exec_control = 0;
u32 _cpu_based_exec_control = 0;
u32 _vmexit_control = 0;
u32 _vmentry_control = 0;

min = PIN_BASED_EXT_INTR_MASK | PIN_BASED_NMI_EXITING;
opt = 0;
if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_PINBASED_CTLS,
&_pin_based_exec_control) < 0)
return -1;

min = CPU_BASED_HLT_EXITING |
#ifdef CONFIG_X86_64
CPU_BASED_CR8_LOAD_EXITING |
CPU_BASED_CR8_STORE_EXITING |
#endif
CPU_BASED_USE_IO_BITMAPS |
CPU_BASED_MOV_DR_EXITING |
CPU_BASED_USE_TSC_OFFSETING;
opt = 0;
if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_PROCBASED_CTLS,
&_cpu_based_exec_control) < 0)
return -1;

min = 0;
#ifdef CONFIG_X86_64
min |= VM_EXIT_HOST_ADDR_SPACE_SIZE;
#endif
opt = 0;
if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_EXIT_CTLS,
&_vmexit_control) < 0)
return -1;

min = opt = 0;
if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_ENTRY_CTLS,
&_vmentry_control) < 0)
return -1;

rdmsr(MSR_IA32_VMX_BASIC, vmx_msr_low, vmx_msr_high);
vmcs_descriptor.size = vmx_msr_high & 0x1fff;
vmcs_descriptor.order = get_order(vmcs_descriptor.size);
vmcs_descriptor.revision_id = vmx_msr_low;

/* IA-32 SDM Vol 3B: VMCS size is never greater than 4kB. */
if ((vmx_msr_high & 0x1fff) > PAGE_SIZE)
return -1;

#ifdef CONFIG_X86_64
/* IA-32 SDM Vol 3B: 64-bit CPUs always have VMX_BASIC_MSR[48]==0. */
if (vmx_msr_high & (1u<<16))
return -1;
#endif

/* Require Write-Back (WB) memory type for VMCS accesses. */
if (((vmx_msr_high >> 18) & 15) != 6)
return -1;

vmcs_config.size = vmx_msr_high & 0x1fff;
vmcs_config.order = get_order(vmcs_config.size);
vmcs_config.revision_id = vmx_msr_low;

vmcs_config.pin_based_exec_ctrl = _pin_based_exec_control;
vmcs_config.cpu_based_exec_ctrl = _cpu_based_exec_control;
vmcs_config.vmexit_ctrl = _vmexit_control;
vmcs_config.vmentry_ctrl = _vmentry_control;

return 0;
}

static struct vmcs *alloc_vmcs_cpu(int cpu)
Expand All @@ -855,12 +933,12 @@ static struct vmcs *alloc_vmcs_cpu(int cpu)
struct page *pages;
struct vmcs *vmcs;

pages = alloc_pages_node(node, GFP_KERNEL, vmcs_descriptor.order);
pages = alloc_pages_node(node, GFP_KERNEL, vmcs_config.order);
if (!pages)
return NULL;
vmcs = page_address(pages);
memset(vmcs, 0, vmcs_descriptor.size);
vmcs->revision_id = vmcs_descriptor.revision_id; /* vmcs revision id */
memset(vmcs, 0, vmcs_config.size);
vmcs->revision_id = vmcs_config.revision_id; /* vmcs revision id */
return vmcs;
}

Expand All @@ -871,7 +949,7 @@ static struct vmcs *alloc_vmcs(void)

static void free_vmcs(struct vmcs *vmcs)
{
free_pages((unsigned long)vmcs, vmcs_descriptor.order);
free_pages((unsigned long)vmcs, vmcs_config.order);
}

static void free_kvm_area(void)
Expand Down Expand Up @@ -904,7 +982,8 @@ static __init int alloc_kvm_area(void)

static __init int hardware_setup(void)
{
setup_vmcs_descriptor();
if (setup_vmcs_config() < 0)
return -1;
return alloc_kvm_area();
}

Expand Down Expand Up @@ -1275,17 +1354,6 @@ static int init_rmode_tss(struct kvm* kvm)
return 1;
}

static void vmcs_write32_fixedbits(u32 msr, u32 vmcs_field, u32 val)
{
u32 msr_high, msr_low;

rdmsr(msr, msr_low, msr_high);

val &= msr_high;
val |= msr_low;
vmcs_write32(vmcs_field, val);
}

static void seg_setup(int seg)
{
struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];
Expand Down Expand Up @@ -1382,20 +1450,10 @@ static int vmx_vcpu_setup(struct kvm_vcpu *vcpu)
vmcs_write64(GUEST_IA32_DEBUGCTL, 0);

/* Control */
vmcs_write32_fixedbits(MSR_IA32_VMX_PINBASED_CTLS,
PIN_BASED_VM_EXEC_CONTROL,
PIN_BASED_EXT_INTR_MASK /* 20.6.1 */
| PIN_BASED_NMI_EXITING /* 20.6.1 */
);
vmcs_write32_fixedbits(MSR_IA32_VMX_PROCBASED_CTLS,
CPU_BASED_VM_EXEC_CONTROL,
CPU_BASED_HLT_EXITING /* 20.6.2 */
| CPU_BASED_CR8_LOAD_EXITING /* 20.6.2 */
| CPU_BASED_CR8_STORE_EXITING /* 20.6.2 */
| CPU_BASED_USE_IO_BITMAPS /* 20.6.2 */
| CPU_BASED_MOV_DR_EXITING
| CPU_BASED_USE_TSC_OFFSETING /* 21.3 */
);
vmcs_write32(PIN_BASED_VM_EXEC_CONTROL,
vmcs_config.pin_based_exec_ctrl);
vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
vmcs_config.cpu_based_exec_ctrl);

vmcs_write32(PAGE_FAULT_ERROR_CODE_MASK, 0);
vmcs_write32(PAGE_FAULT_ERROR_CODE_MATCH, 0);
Expand Down Expand Up @@ -1459,12 +1517,11 @@ static int vmx_vcpu_setup(struct kvm_vcpu *vcpu)

setup_msrs(vcpu);

vmcs_write32_fixedbits(MSR_IA32_VMX_EXIT_CTLS, VM_EXIT_CONTROLS,
(HOST_IS_64 << 9)); /* 22.2,1, 20.7.1 */
vmcs_write32(VM_EXIT_CONTROLS, vmcs_config.vmexit_ctrl);

/* 22.2.1, 20.8.1 */
vmcs_write32_fixedbits(MSR_IA32_VMX_ENTRY_CTLS,
VM_ENTRY_CONTROLS, 0);
vmcs_write32(VM_ENTRY_CONTROLS, vmcs_config.vmentry_ctrl);

vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, 0); /* 22.2.1 */

#ifdef CONFIG_X86_64
Expand Down

0 comments on commit 1c3d14f

Please sign in to comment.