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-rw-r--r--drivers/kvm/kvm.h9
-rw-r--r--drivers/kvm/kvm_main.c89
-rw-r--r--include/linux/kvm.h10
3 files changed, 104 insertions, 4 deletions
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index d19985a..fceeb84 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -51,6 +51,7 @@
#define UNMAPPED_GVA (~(gpa_t)0)
#define KVM_MAX_VCPUS 1
+#define KVM_ALIAS_SLOTS 4
#define KVM_MEMORY_SLOTS 4
#define KVM_NUM_MMU_PAGES 256
#define KVM_MIN_FREE_MMU_PAGES 5
@@ -312,6 +313,12 @@ struct kvm_vcpu {
struct kvm_cpuid_entry cpuid_entries[KVM_MAX_CPUID_ENTRIES];
};
+struct kvm_mem_alias {
+ gfn_t base_gfn;
+ unsigned long npages;
+ gfn_t target_gfn;
+};
+
struct kvm_memory_slot {
gfn_t base_gfn;
unsigned long npages;
@@ -322,6 +329,8 @@ struct kvm_memory_slot {
struct kvm {
spinlock_t lock; /* protects everything except vcpus */
+ int naliases;
+ struct kvm_mem_alias aliases[KVM_ALIAS_SLOTS];
int nmemslots;
struct kvm_memory_slot memslots[KVM_MEMORY_SLOTS];
/*
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index a0ec5dd..e495855 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -846,7 +846,73 @@ out:
return r;
}
-struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
+/*
+ * Set a new alias region. Aliases map a portion of physical memory into
+ * another portion. This is useful for memory windows, for example the PC
+ * VGA region.
+ */
+static int kvm_vm_ioctl_set_memory_alias(struct kvm *kvm,
+ struct kvm_memory_alias *alias)
+{
+ int r, n;
+ struct kvm_mem_alias *p;
+
+ r = -EINVAL;
+ /* General sanity checks */
+ if (alias->memory_size & (PAGE_SIZE - 1))
+ goto out;
+ if (alias->guest_phys_addr & (PAGE_SIZE - 1))
+ goto out;
+ if (alias->slot >= KVM_ALIAS_SLOTS)
+ goto out;
+ if (alias->guest_phys_addr + alias->memory_size
+ < alias->guest_phys_addr)
+ goto out;
+ if (alias->target_phys_addr + alias->memory_size
+ < alias->target_phys_addr)
+ goto out;
+
+ spin_lock(&kvm->lock);
+
+ p = &kvm->aliases[alias->slot];
+ p->base_gfn = alias->guest_phys_addr >> PAGE_SHIFT;
+ p->npages = alias->memory_size >> PAGE_SHIFT;
+ p->target_gfn = alias->target_phys_addr >> PAGE_SHIFT;
+
+ for (n = KVM_ALIAS_SLOTS; n > 0; --n)
+ if (kvm->aliases[n - 1].npages)
+ break;
+ kvm->naliases = n;
+
+ spin_unlock(&kvm->lock);
+
+ vcpu_load(&kvm->vcpus[0]);
+ spin_lock(&kvm->lock);
+ kvm_mmu_zap_all(&kvm->vcpus[0]);
+ spin_unlock(&kvm->lock);
+ vcpu_put(&kvm->vcpus[0]);
+
+ return 0;
+
+out:
+ return r;
+}
+
+static gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
+{
+ int i;
+ struct kvm_mem_alias *alias;
+
+ for (i = 0; i < kvm->naliases; ++i) {
+ alias = &kvm->aliases[i];
+ if (gfn >= alias->base_gfn
+ && gfn < alias->base_gfn + alias->npages)
+ return alias->target_gfn + gfn - alias->base_gfn;
+ }
+ return gfn;
+}
+
+static struct kvm_memory_slot *__gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
{
int i;
@@ -859,13 +925,19 @@ struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
}
return NULL;
}
-EXPORT_SYMBOL_GPL(gfn_to_memslot);
+
+struct kvm_memory_slot *gfn_to_memslot(struct kvm *kvm, gfn_t gfn)
+{
+ gfn = unalias_gfn(kvm, gfn);
+ return __gfn_to_memslot(kvm, gfn);
+}
struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
{
struct kvm_memory_slot *slot;
- slot = gfn_to_memslot(kvm, gfn);
+ gfn = unalias_gfn(kvm, gfn);
+ slot = __gfn_to_memslot(kvm, gfn);
if (!slot)
return NULL;
return slot->phys_mem[gfn - slot->base_gfn];
@@ -2512,6 +2584,17 @@ static long kvm_vm_ioctl(struct file *filp,
goto out;
break;
}
+ case KVM_SET_MEMORY_ALIAS: {
+ struct kvm_memory_alias alias;
+
+ r = -EFAULT;
+ if (copy_from_user(&alias, argp, sizeof alias))
+ goto out;
+ r = kvm_vm_ioctl_set_memory_alias(kvm, &alias);
+ if (r)
+ goto out;
+ break;
+ }
default:
;
}
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 728b24c..da9b23f 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -11,7 +11,7 @@
#include <asm/types.h>
#include <linux/ioctl.h>
-#define KVM_API_VERSION 9
+#define KVM_API_VERSION 10
/*
* Architectural interrupt line count, and the size of the bitmap needed
@@ -33,6 +33,13 @@ struct kvm_memory_region {
/* for kvm_memory_region::flags */
#define KVM_MEM_LOG_DIRTY_PAGES 1UL
+struct kvm_memory_alias {
+ __u32 slot; /* this has a different namespace than memory slots */
+ __u32 flags;
+ __u64 guest_phys_addr;
+ __u64 memory_size;
+ __u64 target_phys_addr;
+};
enum kvm_exit_reason {
KVM_EXIT_UNKNOWN = 0,
@@ -261,6 +268,7 @@ struct kvm_signal_mask {
*/
#define KVM_CREATE_VCPU _IO(KVMIO, 0x41)
#define KVM_GET_DIRTY_LOG _IOW(KVMIO, 0x42, struct kvm_dirty_log)
+#define KVM_SET_MEMORY_ALIAS _IOW(KVMIO, 0x43, struct kvm_memory_alias)
/*
* ioctls for vcpu fds
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