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KVM: VMX: Enable XSAVE/XRSTOR for guest

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This patch enable guest to use XSAVE/XRSTOR instructions.

We assume that host_xcr0 would use all possible bits that OS supported.

And we loaded xcr0 in the same way we handled fpu - do it as late as we can.

Signed-off-by: Dexuan Cui <dexuan.cui@intel.com>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Dexuan Cui 2010-06-10 11:27:12 +08:00 committed by Avi Kivity
parent f495c6e5e8
commit 2acf923e38
6 changed files with 146 additions and 8 deletions
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2
arch/x86/include/asm/kvm_host.h
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@ -302,6 +302,7 @@ struct kvm_vcpu_arch {
} update_pte;
struct fpu guest_fpu;
u64 xcr0;
gva_t mmio_fault_cr2;
struct kvm_pio_request pio;
@ -605,6 +606,7 @@ int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val);
unsigned long kvm_get_cr8(struct kvm_vcpu *vcpu);
void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw);
void kvm_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l);
int kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr);
int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata);
int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data);

1
arch/x86/include/asm/vmx.h
View File

@ -267,6 +267,7 @@ enum vmcs_field {
#define EXIT_REASON_EPT_VIOLATION 48
#define EXIT_REASON_EPT_MISCONFIG 49
#define EXIT_REASON_WBINVD 54
#define EXIT_REASON_XSETBV 55
/*
* Interruption-information format

6
arch/x86/kvm/kvm_cache_regs.h
View File

@ -71,4 +71,10 @@ static inline ulong kvm_read_cr4(struct kvm_vcpu *vcpu)
return kvm_read_cr4_bits(vcpu, ~0UL);
}
static inline u64 kvm_read_edx_eax(struct kvm_vcpu *vcpu)
{
return (kvm_register_read(vcpu, VCPU_REGS_RAX) & -1u)
| ((u64)(kvm_register_read(vcpu, VCPU_REGS_RDX) & -1u) << 32);
}
#endif

13
arch/x86/kvm/vmx.c
View File

@ -37,6 +37,8 @@
#include <asm/vmx.h>
#include <asm/virtext.h>
#include <asm/mce.h>
#include <asm/i387.h>
#include <asm/xcr.h>
#include "trace.h"
@ -3390,6 +3392,16 @@ static int handle_wbinvd(struct kvm_vcpu *vcpu)
return 1;
}
static int handle_xsetbv(struct kvm_vcpu *vcpu)
{
u64 new_bv = kvm_read_edx_eax(vcpu);
u32 index = kvm_register_read(vcpu, VCPU_REGS_RCX);
if (kvm_set_xcr(vcpu, index, new_bv) == 0)
skip_emulated_instruction(vcpu);
return 1;
}
static int handle_apic_access(struct kvm_vcpu *vcpu)
{
return emulate_instruction(vcpu, 0, 0, 0) == EMULATE_DONE;
@ -3668,6 +3680,7 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
[EXIT_REASON_TPR_BELOW_THRESHOLD] = handle_tpr_below_threshold,
[EXIT_REASON_APIC_ACCESS] = handle_apic_access,
[EXIT_REASON_WBINVD] = handle_wbinvd,
[EXIT_REASON_XSETBV] = handle_xsetbv,
[EXIT_REASON_TASK_SWITCH] = handle_task_switch,
[EXIT_REASON_MCE_DURING_VMENTRY] = handle_machine_check,
[EXIT_REASON_EPT_VIOLATION] = handle_ept_violation,

130
arch/x86/kvm/x86.c
View File

@ -65,6 +65,7 @@
(~(unsigned long)(X86_CR4_VME | X86_CR4_PVI | X86_CR4_TSD | X86_CR4_DE\
| X86_CR4_PSE | X86_CR4_PAE | X86_CR4_MCE \
| X86_CR4_PGE | X86_CR4_PCE | X86_CR4_OSFXSR \
| X86_CR4_OSXSAVE \
| X86_CR4_OSXMMEXCPT | X86_CR4_VMXE))
#define CR8_RESERVED_BITS (~(unsigned long)X86_CR8_TPR)
@ -150,6 +151,13 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ NULL }
};
u64 __read_mostly host_xcr0;
static inline u32 bit(int bitno)
{
return 1 << (bitno & 31);
}
static void kvm_on_user_return(struct user_return_notifier *urn)
{
unsigned slot;
@ -474,6 +482,61 @@ void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw)
}
EXPORT_SYMBOL_GPL(kvm_lmsw);
int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
{
u64 xcr0;
/* Only support XCR_XFEATURE_ENABLED_MASK(xcr0) now */
if (index != XCR_XFEATURE_ENABLED_MASK)
return 1;
xcr0 = xcr;
if (kvm_x86_ops->get_cpl(vcpu) != 0)
return 1;
if (!(xcr0 & XSTATE_FP))
return 1;
if ((xcr0 & XSTATE_YMM) && !(xcr0 & XSTATE_SSE))
return 1;
if (xcr0 & ~host_xcr0)
return 1;
vcpu->arch.xcr0 = xcr0;
vcpu->guest_xcr0_loaded = 0;
return 0;
}
int kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
{
if (__kvm_set_xcr(vcpu, index, xcr)) {
kvm_inject_gp(vcpu, 0);
return 1;
}
return 0;
}
EXPORT_SYMBOL_GPL(kvm_set_xcr);
static bool guest_cpuid_has_xsave(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
best = kvm_find_cpuid_entry(vcpu, 1, 0);
return best && (best->ecx & bit(X86_FEATURE_XSAVE));
}
static void update_cpuid(struct kvm_vcpu *vcpu)
{
struct kvm_cpuid_entry2 *best;
best = kvm_find_cpuid_entry(vcpu, 1, 0);
if (!best)
return;
/* Update OSXSAVE bit */
if (cpu_has_xsave && best->function == 0x1) {
best->ecx &= ~(bit(X86_FEATURE_OSXSAVE));
if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE))
best->ecx |= bit(X86_FEATURE_OSXSAVE);
}
}
int __kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
{
unsigned long old_cr4 = kvm_read_cr4(vcpu);
@ -482,6 +545,9 @@ int __kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
if (cr4 & CR4_RESERVED_BITS)
return 1;
if (!guest_cpuid_has_xsave(vcpu) && (cr4 & X86_CR4_OSXSAVE))
return 1;
if (is_long_mode(vcpu)) {
if (!(cr4 & X86_CR4_PAE))
return 1;
@ -498,6 +564,9 @@ int __kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
if ((cr4 ^ old_cr4) & pdptr_bits)
kvm_mmu_reset_context(vcpu);
if ((cr4 ^ old_cr4) & X86_CR4_OSXSAVE)
update_cpuid(vcpu);
return 0;
}
@ -666,11 +735,6 @@ int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val)
}
EXPORT_SYMBOL_GPL(kvm_get_dr);
static inline u32 bit(int bitno)
{
return 1 << (bitno & 31);
}
/*
* List of msr numbers which we expose to userspace through KVM_GET_MSRS
* and KVM_SET_MSRS, and KVM_GET_MSR_INDEX_LIST.
@ -1814,6 +1878,7 @@ static int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
r = 0;
kvm_apic_set_version(vcpu);
kvm_x86_ops->cpuid_update(vcpu);
update_cpuid(vcpu);
out_free:
vfree(cpuid_entries);
@ -1837,6 +1902,7 @@ static int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
vcpu->arch.cpuid_nent = cpuid->nent;
kvm_apic_set_version(vcpu);
kvm_x86_ops->cpuid_update(vcpu);
update_cpuid(vcpu);
return 0;
out:
@ -1917,7 +1983,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
0 /* Reserved */ | F(CX16) | 0 /* xTPR Update, PDCM */ |
0 /* Reserved, DCA */ | F(XMM4_1) |
F(XMM4_2) | F(X2APIC) | F(MOVBE) | F(POPCNT) |
0 /* Reserved, XSAVE, OSXSAVE */;
0 /* Reserved, AES */ | F(XSAVE) | 0 /* OSXSAVE */;
/* cpuid 0x80000001.ecx */
const u32 kvm_supported_word6_x86_features =
F(LAHF_LM) | F(CMP_LEGACY) | F(SVM) | 0 /* ExtApicSpace */ |
@ -1932,7 +1998,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
switch (function) {
case 0:
entry->eax = min(entry->eax, (u32)0xb);
entry->eax = min(entry->eax, (u32)0xd);
break;
case 1:
entry->edx &= kvm_supported_word0_x86_features;
@ -1990,6 +2056,20 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
}
break;
}
case 0xd: {
int i;
entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
for (i = 1; *nent < maxnent; ++i) {
if (entry[i - 1].eax == 0 && i != 2)
break;
do_cpuid_1_ent(&entry[i], function, i);
entry[i].flags |=
KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
++*nent;
}
break;
}
case KVM_CPUID_SIGNATURE: {
char signature[12] = "KVMKVMKVM\0\0";
u32 *sigptr = (u32 *)signature;
@ -4125,6 +4205,9 @@ int kvm_arch_init(void *opaque)
perf_register_guest_info_callbacks(&kvm_guest_cbs);
if (cpu_has_xsave)
host_xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
return 0;
out:
@ -4523,6 +4606,25 @@ static void inject_pending_event(struct kvm_vcpu *vcpu)
}
}
static void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu)
{
if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) &&
!vcpu->guest_xcr0_loaded) {
/* kvm_set_xcr() also depends on this */
xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0);
vcpu->guest_xcr0_loaded = 1;
}
}
static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu)
{
if (vcpu->guest_xcr0_loaded) {
if (vcpu->arch.xcr0 != host_xcr0)
xsetbv(XCR_XFEATURE_ENABLED_MASK, host_xcr0);
vcpu->guest_xcr0_loaded = 0;
}
}
static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
{
int r;
@ -4568,6 +4670,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
kvm_x86_ops->prepare_guest_switch(vcpu);
if (vcpu->fpu_active)
kvm_load_guest_fpu(vcpu);
kvm_load_guest_xcr0(vcpu);
atomic_set(&vcpu->guest_mode, 1);
smp_wmb();
@ -5124,6 +5227,11 @@ int fx_init(struct kvm_vcpu *vcpu)
fpu_finit(&vcpu->arch.guest_fpu);
/*
* Ensure guest xcr0 is valid for loading
*/
vcpu->arch.xcr0 = XSTATE_FP;
vcpu->arch.cr0 |= X86_CR0_ET;
return 0;
@ -5140,6 +5248,12 @@ void kvm_load_guest_fpu(struct kvm_vcpu *vcpu)
if (vcpu->guest_fpu_loaded)
return;
/*
* Restore all possible states in the guest,
* and assume host would use all available bits.
* Guest xcr0 would be loaded later.
*/
kvm_put_guest_xcr0(vcpu);
vcpu->guest_fpu_loaded = 1;
unlazy_fpu(current);
fpu_restore_checking(&vcpu->arch.guest_fpu);
@ -5148,6 +5262,8 @@ void kvm_load_guest_fpu(struct kvm_vcpu *vcpu)
void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
{
kvm_put_guest_xcr0(vcpu);
if (!vcpu->guest_fpu_loaded)
return;

2
include/linux/kvm_host.h
View File

@ -88,7 +88,7 @@ struct kvm_vcpu {
int srcu_idx;
int fpu_active;
int guest_fpu_loaded;
int guest_fpu_loaded, guest_xcr0_loaded;
wait_queue_head_t wq;
int sigset_active;
sigset_t sigset;