Messages in this thread | | | Date | Tue, 16 Apr 2024 08:57:59 -0700 | From | Dan Williams <> | Subject | Re: [PATCH v3 10/14] configfs-tsm: Allow the privlevel_floor attribute to be updated |
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Tom Lendacky wrote: > On 4/15/24 23:55, Dan Williams wrote: > > Tom Lendacky wrote: > >> With the introduction of an SVSM, Linux will be running at a non-zero > >> VMPL. Any request for an attestation report at a higher priviledge VMPL > >> than what Linux is currently running will result in an error. Allow for > >> the privlevel_floor attribute to be updated dynamically so that the > >> attribute may be set dynamically. > >> > >> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> > >> --- > >> drivers/virt/coco/sev-guest/sev-guest.c | 5 ++++- > >> include/linux/tsm.h | 2 +- > >> 2 files changed, 5 insertions(+), 2 deletions(-) > >> > >> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c > >> index 1ff897913bf4..bba6531cb606 100644 > >> --- a/drivers/virt/coco/sev-guest/sev-guest.c > >> +++ b/drivers/virt/coco/sev-guest/sev-guest.c > >> @@ -885,7 +885,7 @@ static int sev_report_new(struct tsm_report *report, void *data) > >> return 0; > >> } > >> > >> -static const struct tsm_ops sev_tsm_ops = { > >> +static struct tsm_ops sev_tsm_ops = { > >> .name = KBUILD_MODNAME, > >> .report_new = sev_report_new, > >> }; > >> @@ -972,6 +972,9 @@ static int __init sev_guest_probe(struct platform_device *pdev) > >> snp_dev->input.resp_gpa = __pa(snp_dev->response); > >> snp_dev->input.data_gpa = __pa(snp_dev->certs_data); > >> > >> + /* Set the privlevel_floor attribute based on the current VMPL */ > >> + sev_tsm_ops.privlevel_floor = snp_get_vmpl(); > > > > Why is this not vmpck_id? > > Good catch, this probably should be pulled out separately and submitted > as a Fixes: against the current support. If you think it's important > enough, I can do that and put this at the beginning of the series. Or I > can just modify this to use the vmpck_id value. Any preference?
I dunno, you tell me. What breaks if privlevel_floor is mismatched vs vmpl and/or vmpck_id? If it warrants a "Fixes:" it should probably be broken out.
However, I *guess* it is just adding some sanity checking precision to userspace requests and makes some input validation not catch errors when userspace tries to generate reports from the wrong level, right? I.e. privlevel_floor may be lower than expected, but userspace should not be depending on that since the report generation will fail.
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