Re: [PATCH v1 18/26] crypto: ccp: Handle legacy SEV commands when SNP is enabled

[Tom Lendacky]

On 1/19/24 11:18, Borislav Petkov wrote:
> On Sat, Dec 30, 2023 at 10:19:46AM -0600, Michael Roth wrote:
> > From: Brijesh Singh <brijesh.singh@xxxxxxx>
> >
> > The behavior of legacy SEV commands is altered when the firmware is
> > initialized for SNP support. In that case, all command buffer memory
> > that may get written to by legacy SEV commands must be marked as
> > firmware-owned in the RMP table prior to issuing the command.
> >
> > Additionally, when a command buffer contains a system physical address
> > that points to additional buffers that firmware may write to, special
> > handling is needed depending on whether:
> >
> >    1) the system physical address points to guest memory
> >    2) the system physical address points to host memory
> >
> > To handle case #1, the pages of these buffers are changed to
> > firmware-owned in the RMP table before issuing the command, and restored
> > to after the command completes.
> >
> > For case #2, a bounce buffer is used instead of the original address.
> >
> > Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
> > Co-developed-by: Michael Roth <michael.roth@xxxxxxx>
> > Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
> > Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
> > ---
> >   drivers/crypto/ccp/sev-dev.c | 421 ++++++++++++++++++++++++++++++++++-
> >   drivers/crypto/ccp/sev-dev.h |   3 +
> >   2 files changed, 414 insertions(+), 10 deletions(-)
>
> Definitely better, thanks.
>
> Some cleanups ontop:
>
> ---

> @@ -904,7 +904,7 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret)
>   		ret = snp_prep_cmd_buf(cmd, cmd_buf, desc_list);
>   		if (ret) {
>   			dev_err(sev->dev,
> -				"SEV: failed to prepare buffer for legacy command %#x. Error: %d\n",
> +				"SEV: failed to prepare buffer for legacy command 0x%#x. Error: %d\n",

Using %#x will produce the 0x in the output (except if the value is zero 
for some reason). So I would say make that 0x%x.

Thanks,
Tom

>   				cmd, ret);
>   			return ret;
>   		}