KVM: MMU: Concurrent guest walkers

[firefly-linux-kernel-4.4.55.git] / arch / x86 / kvm / vmx.c

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d1167fc303d6d70fa66dd03997742fb12c694db0..c39493feba46d01561a525af625d7cf52bb789c0 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1432,27 +1432,34 @@ static int init_rmode_tss(struct kvm *kvm)
 {
        gfn_t fn = rmode_tss_base(kvm) >> PAGE_SHIFT;
        u16 data = 0;
+       int ret = 0;
        int r;
 
+       down_read(&current->mm->mmap_sem);
        r = kvm_clear_guest_page(kvm, fn, 0, PAGE_SIZE);
        if (r < 0)
-               return 0;
+               goto out;
        data = TSS_BASE_SIZE + TSS_REDIRECTION_SIZE;
        r = kvm_write_guest_page(kvm, fn++, &data, 0x66, sizeof(u16));
        if (r < 0)
-               return 0;
+               goto out;
        r = kvm_clear_guest_page(kvm, fn++, 0, PAGE_SIZE);
        if (r < 0)
-               return 0;
+               goto out;
        r = kvm_clear_guest_page(kvm, fn, 0, PAGE_SIZE);
        if (r < 0)
-               return 0;
+               goto out;
        data = ~0;
-       r = kvm_write_guest_page(kvm, fn, &data, RMODE_TSS_SIZE - 2 * PAGE_SIZE - 1,
-                       sizeof(u8));
+       r = kvm_write_guest_page(kvm, fn, &data,
+                                RMODE_TSS_SIZE - 2 * PAGE_SIZE - 1,
+                                sizeof(u8));
        if (r < 0)
-               return 0;
-       return 1;
+               goto out;
+
+       ret = 1;
+out:
+       up_read(&current->mm->mmap_sem);
+       return ret;
 }
 
 static void seg_setup(int seg)
@@ -1471,6 +1478,7 @@ static int alloc_apic_access_page(struct kvm *kvm)
        int r = 0;
 
        mutex_lock(&kvm->lock);
+       down_write(&current->mm->mmap_sem);
        if (kvm->arch.apic_access_page)
                goto out;
        kvm_userspace_mem.slot = APIC_ACCESS_PAGE_PRIVATE_MEMSLOT;
@@ -1482,6 +1490,7 @@ static int alloc_apic_access_page(struct kvm *kvm)
                goto out;
        kvm->arch.apic_access_page = gfn_to_page(kvm, 0xfee00);
 out:
+       up_write(&current->mm->mmap_sem);
        mutex_unlock(&kvm->lock);
        return r;
 }