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KVM: Cache pdptrs 

Instead of reloading the pdptrs on every entry and exit (vmcs writes on vmx,
guest memory access on svm) extract them on demand.

Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Avi Kivity 2009-05-31 22:58:47 +03:00
parent 8f5d549f02
commit 6de4f3ada4
7 changed files with 63 additions and 13 deletions
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4
arch/x86/include/asm/kvm_host.h
View File

@ -120,6 +120,10 @@ enum kvm_reg {
NR_VCPU_REGS
};
enum kvm_reg_ex {
VCPU_EXREG_PDPTR = NR_VCPU_REGS,
};
enum {
VCPU_SREG_ES,
VCPU_SREG_CS,

9
arch/x86/kvm/kvm_cache_regs.h
View File

@ -29,4 +29,13 @@ static inline void kvm_rip_write(struct kvm_vcpu *vcpu, unsigned long val)
kvm_register_write(vcpu, VCPU_REGS_RIP, val);
}
static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index)
{
if (!test_bit(VCPU_EXREG_PDPTR,
(unsigned long *)&vcpu->arch.regs_avail))
kvm_x86_ops->cache_reg(vcpu, VCPU_EXREG_PDPTR);
return vcpu->arch.pdptrs[index];
}
#endif

7
arch/x86/kvm/mmu.c
View File

@ -18,6 +18,7 @@
*/
#include "mmu.h"
#include "kvm_cache_regs.h"
#include <linux/kvm_host.h>
#include <linux/types.h>
@ -1954,6 +1955,7 @@ static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
gfn_t root_gfn;
struct kvm_mmu_page *sp;
int direct = 0;
u64 pdptr;
root_gfn = vcpu->arch.cr3 >> PAGE_SHIFT;
@ -1981,11 +1983,12 @@ static int mmu_alloc_roots(struct kvm_vcpu *vcpu)
ASSERT(!VALID_PAGE(root));
if (vcpu->arch.mmu.root_level == PT32E_ROOT_LEVEL) {
if (!is_present_pte(vcpu->arch.pdptrs[i])) {
pdptr = kvm_pdptr_read(vcpu, i);
if (!is_present_pte(pdptr)) {
vcpu->arch.mmu.pae_root[i] = 0;
continue;
}
root_gfn = vcpu->arch.pdptrs[i] >> PAGE_SHIFT;
root_gfn = pdptr >> PAGE_SHIFT;
} else if (vcpu->arch.mmu.root_level == 0)
root_gfn = 0;
if (mmu_check_root(vcpu, root_gfn))

2
arch/x86/kvm/paging_tmpl.h
View File

@ -131,7 +131,7 @@ static int FNAME(walk_addr)(struct guest_walker *walker,
pte = vcpu->arch.cr3;
#if PTTYPE == 64
if (!is_long_mode(vcpu)) {
pte = vcpu->arch.pdptrs[(addr >> 30) & 3];
pte = kvm_pdptr_read(vcpu, (addr >> 30) & 3);
if (!is_present_pte(pte))
goto not_present;
--walker->level;

24
arch/x86/kvm/svm.c
View File

@ -777,6 +777,18 @@ static void svm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
to_svm(vcpu)->vmcb->save.rflags = rflags;
}
static void svm_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
{
switch (reg) {
case VCPU_EXREG_PDPTR:
BUG_ON(!npt_enabled);
load_pdptrs(vcpu, vcpu->arch.cr3);
break;
default:
BUG();
}
}
static void svm_set_vintr(struct vcpu_svm *svm)
{
svm->vmcb->control.intercept |= 1ULL << INTERCEPT_VINTR;
@ -2285,12 +2297,6 @@ static int handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
}
vcpu->arch.cr0 = svm->vmcb->save.cr0;
vcpu->arch.cr3 = svm->vmcb->save.cr3;
if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
if (!load_pdptrs(vcpu, vcpu->arch.cr3)) {
kvm_inject_gp(vcpu, 0);
return 1;
}
}
if (mmu_reload) {
kvm_mmu_reset_context(vcpu);
kvm_mmu_load(vcpu);
@ -2641,6 +2647,11 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
svm->next_rip = 0;
if (npt_enabled) {
vcpu->arch.regs_avail &= ~(1 << VCPU_EXREG_PDPTR);
vcpu->arch.regs_dirty &= ~(1 << VCPU_EXREG_PDPTR);
}
svm_complete_interrupts(svm);
}
@ -2749,6 +2760,7 @@ static struct kvm_x86_ops svm_x86_ops = {
.set_gdt = svm_set_gdt,
.get_dr = svm_get_dr,
.set_dr = svm_set_dr,
.cache_reg = svm_cache_reg,
.get_rflags = svm_get_rflags,
.set_rflags = svm_set_rflags,

22
arch/x86/kvm/vmx.c
View File

@ -161,6 +161,8 @@ static struct kvm_vmx_segment_field {
VMX_SEGMENT_FIELD(LDTR),
};
static void ept_save_pdptrs(struct kvm_vcpu *vcpu);
/*
* Keep MSR_K6_STAR at the end, as setup_msrs() will try to optimize it
* away by decrementing the array size.
@ -1047,6 +1049,10 @@ static void vmx_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
case VCPU_REGS_RIP:
vcpu->arch.regs[VCPU_REGS_RIP] = vmcs_readl(GUEST_RIP);
break;
case VCPU_EXREG_PDPTR:
if (enable_ept)
ept_save_pdptrs(vcpu);
break;
default:
break;
}
@ -1546,6 +1552,10 @@ static void vmx_decache_cr4_guest_bits(struct kvm_vcpu *vcpu)
static void ept_load_pdptrs(struct kvm_vcpu *vcpu)
{
if (!test_bit(VCPU_EXREG_PDPTR,
(unsigned long *)&vcpu->arch.regs_dirty))
return;
if (is_paging(vcpu) && is_pae(vcpu) && !is_long_mode(vcpu)) {
vmcs_write64(GUEST_PDPTR0, vcpu->arch.pdptrs[0]);
vmcs_write64(GUEST_PDPTR1, vcpu->arch.pdptrs[1]);
@ -1562,6 +1572,11 @@ static void ept_save_pdptrs(struct kvm_vcpu *vcpu)
vcpu->arch.pdptrs[2] = vmcs_read64(GUEST_PDPTR2);
vcpu->arch.pdptrs[3] = vmcs_read64(GUEST_PDPTR3);
}
__set_bit(VCPU_EXREG_PDPTR,
(unsigned long *)&vcpu->arch.regs_avail);
__set_bit(VCPU_EXREG_PDPTR,
(unsigned long *)&vcpu->arch.regs_dirty);
}
static void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4);
@ -3255,10 +3270,8 @@ static int vmx_handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
/* Access CR3 don't cause VMExit in paging mode, so we need
* to sync with guest real CR3. */
if (enable_ept && is_paging(vcpu)) {
if (enable_ept && is_paging(vcpu))
vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
ept_save_pdptrs(vcpu);
}
if (unlikely(vmx->fail)) {
kvm_run->exit_reason = KVM_EXIT_FAIL_ENTRY;
@ -3567,7 +3580,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
#endif
);
vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP));
vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP)
| (1 << VCPU_EXREG_PDPTR));
vcpu->arch.regs_dirty = 0;
get_debugreg(vcpu->arch.dr6, 6);

8
arch/x86/kvm/x86.c
View File

@ -246,6 +246,10 @@ int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3)
ret = 1;
memcpy(vcpu->arch.pdptrs, pdpte, sizeof(vcpu->arch.pdptrs));
__set_bit(VCPU_EXREG_PDPTR,
(unsigned long *)&vcpu->arch.regs_avail);
__set_bit(VCPU_EXREG_PDPTR,
(unsigned long *)&vcpu->arch.regs_dirty);
out:
return ret;
@ -261,6 +265,10 @@ static bool pdptrs_changed(struct kvm_vcpu *vcpu)
if (is_long_mode(vcpu) || !is_pae(vcpu))
return false;
if (!test_bit(VCPU_EXREG_PDPTR,
(unsigned long *)&vcpu->arch.regs_avail))
return true;
r = kvm_read_guest(vcpu->kvm, vcpu->arch.cr3 & ~31u, pdpte, sizeof(pdpte));
if (r < 0)
goto out;