When SEV is enabled, the hardware encryption engine uses a tweak such
that the two identical plaintext at different location will have a
different ciphertexts. So swapping or moving a ciphertexts of two guest
pages will not result in plaintexts being swapped. Hence relocating
a physical backing pages of the SEV guest will require some additional
steps in KVM driver. The KVM_MEMORY_ENCRYPT_{UN,}REG_REGION ioctl can be
used to register/unregister the guest memory region which may contain the
encrypted data. KVM driver will internally handle the relocating physical
backing pages of registered memory regions.
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Richard Henderson <rth@xxxxxxxxxxx>
Cc: Eduardo Habkost <ehabkost@xxxxxxxxxx>
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---
target/i386/sev.c | 41 +++++++++++++++++++++++++++++++++++++++++
target/i386/trace-events | 2 ++
2 files changed, 43 insertions(+)
diff --git a/target/i386/sev.c b/target/i386/sev.c
index 80569f4bcf49..8ee6159b2bfc 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -100,6 +100,45 @@ fw_error_to_str(int code)
return sev_fw_errlist[code];
}
+static void
+sev_ram_block_added(RAMBlockNotifier *n, void *host, size_t size)
+{
+ int r;
+ struct kvm_enc_region range;
+
+ range.addr = (__u64)host;
+ range.size = size;
+
+ trace_kvm_memcrypt_register_region(host, size);
+ r = kvm_vm_ioctl(kvm_state, KVM_MEMORY_ENCRYPT_REG_REGION, &range);
+ if (r) {
+ error_report("%s: failed to register region (%p+%#lx)",
+ __func__, host, size);
+ }
+}
+
+static void
+sev_ram_block_removed(RAMBlockNotifier *n, void *host, size_t size)
+{
+ int r;
+ struct kvm_enc_region range;
+
+ range.addr = (__u64)host;
+ range.size = size;
+
+ trace_kvm_memcrypt_unregister_region(host, size);
+ r = kvm_vm_ioctl(kvm_state, KVM_MEMORY_ENCRYPT_UNREG_REGION, &range);
+ if (r) {
+ error_report("%s: failed to unregister region (%p+%#lx)",
+ __func__, host, size);
+ }
+}
+
+static struct RAMBlockNotifier sev_ram_notifier = {
+ .ram_block_added = sev_ram_block_added,
+ .ram_block_removed = sev_ram_block_removed,
+};
+
static void
qsev_guest_finalize(Object *obj)
{
@@ -434,6 +473,8 @@ sev_guest_init(const char *id)
goto err;
}
+ ram_block_notifier_add(&sev_ram_notifier);
+
return s;
err:
g_free(sev_state);
diff --git a/target/i386/trace-events b/target/i386/trace-events
index 797b716751b7..ffa3d2250425 100644
--- a/target/i386/trace-events
+++ b/target/i386/trace-events
@@ -8,3 +8,5 @@ kvm_x86_update_msi_routes(int num) "Updated %d MSI routes"
# target/i386/sev.c
kvm_sev_init(void) ""
+kvm_memcrypt_register_region(void *addr, size_t len) "addr %p len 0x%lu"
+kvm_memcrypt_unregister_region(void *addr, size_t len) "addr %p len 0x%lu"
--
2.14.3
