On 26/04/2023 21:27, Jason Andryuk wrote:
Hi, Jennifer,
On Tue, Apr 25, 2023 at 1:48 PM Jennifer Herbert
<jennifer.herb...@citrix.com> wrote:
This patch makes the TPM version, for which the ACPI libary probes,
configurable.
If acpi_config.tpm_verison is set to 1, it indicates that 1.2 (TCPA) should be
probed.
I have also added to hvmloader an option to allow setting this new config,
which can
be triggered by setting the platform/tpm_version xenstore key.
Signed-off-by: Jennifer Herbert <jennifer.herb...@citrix.com>
...
--- a/tools/libacpi/build.c
+++ b/tools/libacpi/build.c
@@ -409,38 +409,47 @@ static int construct_secondary_tables(struct acpi_ctxt
*ctxt,
...
+ switch ( config->tpm_version )
{
- tcpa->lasa = ctxt->mem_ops.v2p(ctxt, lasa);
- tcpa->laml = ACPI_2_0_TCPA_LAML_SIZE;
- memset(lasa, 0, tcpa->laml);
- set_checksum(tcpa,
- offsetof(struct acpi_header, checksum),
- tcpa->header.length);
+ case 0: /* Assume legacy code wanted tpm 1.2 */
This shouldn't be reached, since tpm_version == 0 won't have
ACPI_HAS_TPM set. Still, do you want to make it a break or drop the
case to avoid falling through to the TPM1.2 code?
So there was concerns in v2 about backward compatilibity before of this
area of code. The exact nature of the concern was vauge, so I made this
very conservative. This was intended to mitigate agaist this code
being run, but with the structure being set up with something other
then the code in tools/firmware/hvmloader/util.c. Any such alaternate
code would set the tpm flag, but not know about the version field, and
so leave it at zero. In this case, dropping into 1.2 probing would be
the correct solution.
As you say, in the use cases I'm farmiliar with, this would not get
reached, so shoudn't affect anything.
Haveing a break or dropping the case would result in it silently
ignoring the 'invalid' tpm configuration, so if not compatibilty mode,
I'd personally prefer some sort of assert, although i'm not sure how
best to do that in this code.
-jenny
Looks good though.
Reviewed-by: Jason Andryuk <jandr...@gmail.com>
Thanks,
Jason
