Commit 0f346074 authored by Izik Eidus's avatar Izik Eidus Committed by Avi Kivity
Browse files

KVM: remove the vmap usage 



vmap() on guest pages hides those pages from the Linux mm for an extended
(userspace determined) amount of time.  Get rid of it.

Signed-off-by: default avatarIzik Eidus <ieidus@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 77c2002e

arch/x86/kvm/x86.c

+13 −49
Original line number Diff line number Diff line
@@ -2371,40 +2371,19 @@ int emulate_instruction(struct kvm_vcpu *vcpu, 
}

EXPORT_SYMBOL_GPL(emulate_instruction);



static void free_pio_guest_pages(struct kvm_vcpu *vcpu)

{

	int i;



	for (i = 0; i < ARRAY_SIZE(vcpu->arch.pio.guest_pages); ++i)

		if (vcpu->arch.pio.guest_pages[i]) {

			kvm_release_page_dirty(vcpu->arch.pio.guest_pages[i]);

			vcpu->arch.pio.guest_pages[i] = NULL;

		}

}



static int pio_copy_data(struct kvm_vcpu *vcpu)

{

	void *p = vcpu->arch.pio_data;

	void *q;

	gva_t q = vcpu->arch.pio.guest_gva;

	unsigned bytes;

	int nr_pages = vcpu->arch.pio.guest_pages[1] ? 2 : 1;

	int ret;



	q = vmap(vcpu->arch.pio.guest_pages, nr_pages, VM_READ|VM_WRITE,

		 PAGE_KERNEL);

	if (!q) {

		free_pio_guest_pages(vcpu);

		return -ENOMEM;

	}

	q += vcpu->arch.pio.guest_page_offset;

	bytes = vcpu->arch.pio.size * vcpu->arch.pio.cur_count;

	if (vcpu->arch.pio.in)

		memcpy(q, p, bytes);

		ret = kvm_write_guest_virt(q, p, bytes, vcpu);

	else

		memcpy(p, q, bytes);

	q -= vcpu->arch.pio.guest_page_offset;

	vunmap(q);

	free_pio_guest_pages(vcpu);

	return 0;

		ret = kvm_read_guest_virt(q, p, bytes, vcpu);

	return ret;

}



int complete_pio(struct kvm_vcpu *vcpu)
@@ -2515,7 +2494,6 @@ int kvm_emulate_pio(struct kvm_vcpu *vcpu, struct kvm_run *run, int in, 
	vcpu->arch.pio.in = in;

	vcpu->arch.pio.string = 0;

	vcpu->arch.pio.down = 0;

	vcpu->arch.pio.guest_page_offset = 0;

	vcpu->arch.pio.rep = 0;



	if (vcpu->run->io.direction == KVM_EXIT_IO_IN)
@@ -2543,9 +2521,7 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in, 
		  gva_t address, int rep, unsigned port)

{

	unsigned now, in_page;

	int i, ret = 0;

	int nr_pages = 1;

	struct page *page;

	int ret = 0;

	struct kvm_io_device *pio_dev;



	vcpu->run->exit_reason = KVM_EXIT_IO;
@@ -2557,7 +2533,6 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in, 
	vcpu->arch.pio.in = in;

	vcpu->arch.pio.string = 1;

	vcpu->arch.pio.down = down;

	vcpu->arch.pio.guest_page_offset = offset_in_page(address);

	vcpu->arch.pio.rep = rep;



	if (vcpu->run->io.direction == KVM_EXIT_IO_IN)
@@ -2577,15 +2552,8 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in, 
	else

		in_page = offset_in_page(address) + size;

	now = min(count, (unsigned long)in_page / size);

	if (!now) {

		/*

		 * String I/O straddles page boundary.  Pin two guest pages

		 * so that we satisfy atomicity constraints.  Do just one

		 * transaction to avoid complexity.

		 */

		nr_pages = 2;

	if (!now)

		now = 1;

	}

	if (down) {

		/*

		 * String I/O in reverse.  Yuck.  Kill the guest, fix later.
@@ -2600,15 +2568,7 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in, 
	if (vcpu->arch.pio.cur_count == vcpu->arch.pio.count)

		kvm_x86_ops->skip_emulated_instruction(vcpu);



	for (i = 0; i < nr_pages; ++i) {

		page = gva_to_page(vcpu, address + i * PAGE_SIZE);

		vcpu->arch.pio.guest_pages[i] = page;

		if (!page) {

			kvm_inject_gp(vcpu, 0);

			free_pio_guest_pages(vcpu);

			return 1;

		}

	}

	vcpu->arch.pio.guest_gva = address;



	pio_dev = vcpu_find_pio_dev(vcpu, port,

				    vcpu->arch.pio.cur_count,
@@ -2616,7 +2576,11 @@ int kvm_emulate_pio_string(struct kvm_vcpu *vcpu, struct kvm_run *run, int in, 
	if (!vcpu->arch.pio.in) {

		/* string PIO write */

		ret = pio_copy_data(vcpu);

		if (ret >= 0 && pio_dev) {

		if (ret == X86EMUL_PROPAGATE_FAULT) {

			kvm_inject_gp(vcpu, 0);

			return 1;

		}

		if (ret == 0 && pio_dev) {

			pio_string_write(pio_dev, vcpu);

			complete_pio(vcpu);

			if (vcpu->arch.pio.count == 0)

include/linux/kvm_types.h

+1 −2
Original line number Diff line number Diff line
@@ -43,8 +43,7 @@ typedef hfn_t pfn_t; 
struct kvm_pio_request {

	unsigned long count;

	int cur_count;

	struct page *guest_pages[2];

	unsigned guest_page_offset;

	gva_t guest_gva;

	int in;

	int port;

	int size;