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Commit 6de4f3ad authored by Avi Kivity's avatar Avi Kivity
Browse files

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: default avatarAvi Kivity <avi@redhat.com>
parent 8f5d549f

arch/x86/include/asm/kvm_host.h

+4 −0
Original line number Diff line number Diff line
@@ -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,

arch/x86/kvm/kvm_cache_regs.h

+9 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/kvm/mmu.c

+5 −2
Original line number Diff line number Diff line
@@ -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))

arch/x86/kvm/paging_tmpl.h

+1 −1
Original line number Diff line number Diff line
@@ -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;

arch/x86/kvm/svm.c

+18 −6
Original line number Diff line number Diff line
@@ -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,