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: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 67f9176..2a4f3a6 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -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)

diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
index 9b6f395..5f4a18c 100644 (file)
--- a/include/linux/kvm_types.h
+++ b/include/linux/kvm_types.h
@@ -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;