From 6de4f3ada40b336522250a7832a0cc4de8856589 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Sun, 31 May 2009 22:58:47 +0300 Subject: [PATCH] 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 --- arch/x86/include/asm/kvm_host.h | 4 ++++ arch/x86/kvm/kvm_cache_regs.h | 9 +++++++++ arch/x86/kvm/mmu.c | 7 +++++-- arch/x86/kvm/paging_tmpl.h | 2 +- arch/x86/kvm/svm.c | 24 ++++++++++++++++++------ arch/x86/kvm/vmx.c | 22 ++++++++++++++++++---- arch/x86/kvm/x86.c | 8 ++++++++ 7 files changed, 63 insertions(+), 13 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 81c68f630b14..1cc901ec4ba5 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -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, diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index 1ff819dce7d3..7bcc5b6a4403 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -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 diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 0ef5bb2b4043..8ee67e3fb9d0 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -18,6 +18,7 @@ */ #include "mmu.h" +#include "kvm_cache_regs.h" #include #include @@ -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)) diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 67785f635399..4cb1dbfd7c2a 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -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; diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 522e69597a16..7749b0692cb2 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -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, diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 752465f98bfd..d726dec69529 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -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); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 75e9df097845..2ad8c97f58cc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -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; -- GitLab