KVM: VMX: Introduce KVM_SET_IDENTITY_MAP_ADDR ioctl
Now KVM allow guest to modify guest's physical address of EPT's identity mapping page.
(change from v1, discard unnecessary check, change ioctl to accept parameter
address rather than value)
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 08732d7..e210b21 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -411,6 +411,7 @@
struct page *ept_identity_pagetable;
bool ept_identity_pagetable_done;
+ gpa_t ept_identity_map_addr;
unsigned long irq_sources_bitmap;
unsigned long irq_states[KVM_IOAPIC_NUM_PINS];
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c6256b9..686e1ab 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1719,7 +1719,7 @@
eptp = construct_eptp(cr3);
vmcs_write64(EPT_POINTER, eptp);
guest_cr3 = is_paging(vcpu) ? vcpu->arch.cr3 :
- VMX_EPT_IDENTITY_PAGETABLE_ADDR;
+ vcpu->kvm->arch.ept_identity_map_addr;
}
vmx_flush_tlb(vcpu);
@@ -2122,7 +2122,7 @@
if (likely(kvm->arch.ept_identity_pagetable_done))
return 1;
ret = 0;
- identity_map_pfn = VMX_EPT_IDENTITY_PAGETABLE_ADDR >> PAGE_SHIFT;
+ identity_map_pfn = kvm->arch.ept_identity_map_addr >> PAGE_SHIFT;
r = kvm_clear_guest_page(kvm, identity_map_pfn, 0, PAGE_SIZE);
if (r < 0)
goto out;
@@ -2191,14 +2191,15 @@
goto out;
kvm_userspace_mem.slot = IDENTITY_PAGETABLE_PRIVATE_MEMSLOT;
kvm_userspace_mem.flags = 0;
- kvm_userspace_mem.guest_phys_addr = VMX_EPT_IDENTITY_PAGETABLE_ADDR;
+ kvm_userspace_mem.guest_phys_addr =
+ kvm->arch.ept_identity_map_addr;
kvm_userspace_mem.memory_size = PAGE_SIZE;
r = __kvm_set_memory_region(kvm, &kvm_userspace_mem, 0);
if (r)
goto out;
kvm->arch.ept_identity_pagetable = gfn_to_page(kvm,
- VMX_EPT_IDENTITY_PAGETABLE_ADDR >> PAGE_SHIFT);
+ kvm->arch.ept_identity_map_addr >> PAGE_SHIFT);
out:
up_write(&kvm->slots_lock);
return r;
@@ -3814,9 +3815,13 @@
if (alloc_apic_access_page(kvm) != 0)
goto free_vmcs;
- if (enable_ept)
+ if (enable_ept) {
+ if (!kvm->arch.ept_identity_map_addr)
+ kvm->arch.ept_identity_map_addr =
+ VMX_EPT_IDENTITY_PAGETABLE_ADDR;
if (alloc_identity_pagetable(kvm) != 0)
goto free_vmcs;
+ }
return &vmx->vcpu;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c7ec0c9..f4cb1ba 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1206,6 +1206,7 @@
case KVM_CAP_IOEVENTFD:
case KVM_CAP_PIT2:
case KVM_CAP_PIT_STATE2:
+ case KVM_CAP_SET_IDENTITY_MAP_ADDR:
r = 1;
break;
case KVM_CAP_COALESCED_MMIO:
@@ -1906,6 +1907,13 @@
return ret;
}
+static int kvm_vm_ioctl_set_identity_map_addr(struct kvm *kvm,
+ u64 ident_addr)
+{
+ kvm->arch.ept_identity_map_addr = ident_addr;
+ return 0;
+}
+
static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm,
u32 kvm_nr_mmu_pages)
{
@@ -2173,6 +2181,17 @@
if (r < 0)
goto out;
break;
+ case KVM_SET_IDENTITY_MAP_ADDR: {
+ u64 ident_addr;
+
+ r = -EFAULT;
+ if (copy_from_user(&ident_addr, argp, sizeof ident_addr))
+ goto out;
+ r = kvm_vm_ioctl_set_identity_map_addr(kvm, ident_addr);
+ if (r < 0)
+ goto out;
+ break;
+ }
case KVM_SET_MEMORY_REGION: {
struct kvm_memory_region kvm_mem;
struct kvm_userspace_memory_region kvm_userspace_mem;
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 230a91a..f8f8900 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -435,6 +435,7 @@
#define KVM_CAP_PIT_STATE2 35
#endif
#define KVM_CAP_IOEVENTFD 36
+#define KVM_CAP_SET_IDENTITY_MAP_ADDR 37
#ifdef KVM_CAP_IRQ_ROUTING
@@ -512,6 +513,7 @@
#define KVM_SET_USER_MEMORY_REGION _IOW(KVMIO, 0x46,\
struct kvm_userspace_memory_region)
#define KVM_SET_TSS_ADDR _IO(KVMIO, 0x47)
+#define KVM_SET_IDENTITY_MAP_ADDR _IOW(KVMIO, 0x48, __u64)
/* Device model IOC */
#define KVM_CREATE_IRQCHIP _IO(KVMIO, 0x60)
#define KVM_IRQ_LINE _IOW(KVMIO, 0x61, struct kvm_irq_level)