On 11/16/22 10:23, Peter Gonda wrote:
On Wed, Nov 16, 2022 at 5:20 AM Borislav Petkov <bp@xxxxxxx> wrote:
On Tue, Nov 15, 2022 at 02:47:31PM -0700, Peter Gonda wrote:
+ * certificate data buffer retry the same guest request without the
+ * extended data request.
+ */
+ if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST &&
+ err == SNP_GUEST_REQ_INVALID_LEN) {
+ const unsigned int certs_npages = snp_dev->input.data_npages;
+
+ exit_code = SVM_VMGEXIT_GUEST_REQUEST;
+ rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err);
+
+ err = SNP_GUEST_REQ_INVALID_LEN;
Huh, why are we overwriting err here?
I have added a comment for the next revision.
We are overwriting err here so that userspace is alerted that they
supplied a buffer too small.
Sure but you're not checking rc either. What if that reissue fails for
whatever other reason? -EIO for example...
If we get any error here we have to wipe the VMPCK here so I thought
More accurate to say that you will wipe the VMPCK, since the value of rc
is checked a bit further down in the code and the -EIO (or other non-zero)
will be result in a call to snp_disable_vmpck() and rc being propagated
back to the user as an ioctl() return code.
Might be worth a comment above that second snp_issue_guest_request()
explaining that.
this always override @err was OK.
I can update this to only override @err if after the secondary
SVM_VMGEXIT_GUEST_REQUEST rc and err are OK. Thoughts?
I think it's ok to set it no matter what, but I don't have a strong
opinion either way.
Thanks,
Tom
--
Regards/Gruss,
Boris.
SUSE Software Solutions Germany GmbH
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Martje Boudien Moerman
(HRB 36809, AG Nürnberg)
