The command copies a plain text into guest memory and encrypts it using
the VM encryption key. The command will be used for debug purposes
(e.g setting breakpoint through gdbserver)
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---
arch/x86/kvm/svm.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 87 insertions(+)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index ce8819a..64899ed 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6058,6 +6058,89 @@ static int sev_dbg_decrypt(struct kvm *kvm, struct kvm_sev_cmd *argp)
return ret;
}
+static int sev_dbg_encrypt(struct kvm *kvm, struct kvm_sev_cmd *argp)
+{
+ void *data;
+ int len, ret, d_off;
+ struct page **inpages;
+ struct kvm_sev_dbg debug;
+ struct sev_data_dbg *encrypt;
+ unsigned long src_addr, dst_addr, npages;
+
+ if (!sev_guest(kvm))
+ return -ENOTTY;
+
+ if (copy_from_user(&debug, argp, sizeof(*argp)))
+ return -EFAULT;
+
+ if (debug.length > PAGE_SIZE)
+ return -EINVAL;
+
+ len = debug.length;
+ src_addr = debug.src_addr;
+ dst_addr = debug.dst_addr;
+
+ inpages = sev_pin_memory(dst_addr, PAGE_SIZE, &npages);
+ if (!inpages)
+ return -EFAULT;
+
+ encrypt = kzalloc(sizeof(*encrypt), GFP_KERNEL);
+ if (!encrypt) {
+ ret = -ENOMEM;
+ goto err_1;
+ }
+
+ data = (void *) get_zeroed_page(GFP_KERNEL);
+ if (!data) {
+ ret = -ENOMEM;
+ goto err_2;
+ }
+
+ if ((len & 15) || (dst_addr & 15)) {
+ /* if destination address and length are not 16-byte
+ * aligned then:
+ * a) decrypt destination page into temporary buffer
+ * b) copy source data into temporary buffer at correct offset
+ * c) encrypt temporary buffer
+ */
+ ret = __sev_dbg_decrypt_page(kvm, dst_addr, data, &argp->error);
+ if (ret)
+ goto err_3;
+ d_off = dst_addr & (PAGE_SIZE - 1);
+
+ if (copy_from_user(data + d_off,
+ (uint8_t *)debug.src_addr, len)) {
+ ret = -EFAULT;
+ goto err_3;
+ }
+
+ encrypt->length = PAGE_SIZE;
+ encrypt->src_addr = __psp_pa(data);
+ encrypt->dst_addr = __sev_page_pa(inpages[0]);
+ } else {
+ if (copy_from_user(data, (uint8_t *)debug.src_addr, len)) {
+ ret = -EFAULT;
+ goto err_3;
+ }
+
+ d_off = dst_addr & (PAGE_SIZE - 1);
+ encrypt->length = len;
+ encrypt->src_addr = __psp_pa(data);
+ encrypt->dst_addr = __sev_page_pa(inpages[0]);
+ encrypt->dst_addr += d_off;
+ }
+
+ encrypt->handle = sev_get_handle(kvm);
+ ret = sev_issue_cmd(kvm, SEV_CMD_DBG_ENCRYPT, encrypt, &argp->error);
+err_3:
+ free_page((unsigned long)data);
+err_2:
+ kfree(encrypt);
+err_1:
+ sev_unpin_memory(inpages, npages);
+ return ret;
+}
+
static int amd_memory_encryption_cmd(struct kvm *kvm, void __user *argp)
{
int r = -ENOTTY;
@@ -6089,6 +6172,10 @@ static int amd_memory_encryption_cmd(struct kvm *kvm, void __user *argp)
r = sev_dbg_decrypt(kvm, &sev_cmd);
break;
}
+ case KVM_SEV_DBG_ENCRYPT: {
+ r = sev_dbg_encrypt(kvm, &sev_cmd);
+ break;
+ }
default:
break;
}
--
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