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>
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---
accel/kvm/sev.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/accel/kvm/sev.c b/accel/kvm/sev.c
index 37020751bd14..7b5318993969 100644
--- a/accel/kvm/sev.c
+++ b/accel/kvm/sev.c
@@ -84,6 +84,43 @@ fw_error_to_str(int 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;
+
+ r = kvm_vm_ioctl(kvm_state, KVM_MEMORY_ENCRYPT_REG_REGION, &range);
+ if (r) {
+ error_report("%s: failed to register region (%#llx+%#llx)",
+ __func__, range.addr, range.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;
+
+ r = kvm_vm_ioctl(kvm_state, KVM_MEMORY_ENCRYPT_UNREG_REGION, &range);
+ if (r) {
+ error_report("%s: failed to unregister region (%#llx+%#llx)",
+ __func__, range.addr, range.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)
{
}
@@ -286,6 +323,8 @@ sev_guest_init(const char *id)
goto err;
}
+ ram_block_notifier_add(&sev_ram_notifier);
+
return s;
err:
g_free(s);
--
2.9.5
