On 11/10/2022 7:39 AM, Michael Roth wrote:
- * bp->cc_blob_address should only be set by boot/compressed kernel.
- * Initialize it to 0 to ensure that uninitialized values from
- * buggy bootloaders aren't propagated.
+ * bp->cc_blob_address should only be set by boot/compressed
+ * kernel and hypervisor with direct boot mode. Initialize it
+ * to 0 after checking in order to ensure that uninitialized
+ * values from buggy bootloaders aren't propagated.
*/
- if (bp)
- bp->cc_blob_address = 0;
+ if (bp) {
+ cc_info = (struct cc_blob_sev_info *)(unsigned long)
+ bp->cc_blob_address;
+
+ if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
+ bp->cc_blob_address = 0;
It doesn't seem great to rely on SEV_HDR_MAGIC to determine whether
bp->cc_blob_address is valid or not since it is only a 32-bit value.
Would it be possible to use a setup_data entry of type SETUP_CC_BLOB
in bp->hdr.setup_data instead? There's already handling for that in
find_cc_blob_setup_data() so it should "just work".
Hi Michael:
Thanks for your review. I will have a try. Hypervisor may set
cc_blob_address directly and so propose this.
