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>

1 files changed, 13 insertions, 49 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 67f91764e99b..2a4f3a697343 100644
--- 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)