From: Dan Williams <dan.j.williams@intel.com>
To: Alexey Kardashevskiy <aik@amd.com>,
Dan Williams <dan.j.williams@intel.com>,
<linux-coco@lists.linux.dev>
Cc: Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Dionna Amalie Glaze <dionnaglaze@google.com>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
Peter Gonda <pgonda@google.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Samuel Ortiz <sameo@rivosinc.com>,
Thomas Gleixner <tglx@linutronix.de>, <peterz@infradead.org>,
<dave.hansen@linux.intel.com>, <bp@alien8.de>
Subject: Re: [PATCH v6 3/7] configfs-tsm: Introduce a shared ABI for attestation reports
Date: Thu, 19 Oct 2023 13:24:15 -0700 [thread overview]
Message-ID: <6531906fc5494_f87929441@dwillia2-mobl3.amr.corp.intel.com.notmuch> (raw)
In-Reply-To: <d6515cba-1751-417b-ab11-980010472aa4@amd.com>
Alexey Kardashevskiy wrote:
[..]
> >>> + size_t count, enum tsm_data_select select)
> >>> +{
> >>> + struct tsm_report_state *state = to_state(report);
> >>> + const struct tsm_ops *ops;
> >>> + ssize_t rc;
> >>> +
> >>> + /* try to read from the existing report if present and valid... */
> >>> + rc = read_cached_report(report, buf, count, select);
> >>> + if (rc >= 0 || rc != -EWOULDBLOCK)
> >>> + return rc;
> >>> +
> >>> + /* slow path, report may need to be regenerated... */
> >>> + guard(rwsem_write)(&tsm_rwsem);
> >>> + ops = provider.ops;
> >>> + if (!report->desc.inblob_len)
> >>> + return -EINVAL;
> >>> +
> >>> + /* did another thread already generate this report? */
> >>> + if (report->outblob &&
> >>> + state->read_generation == state->write_generation)
> >>> + goto out;
> >>> + kvfree(report->outblob);
> >>> + kvfree(report->auxblob);
> >>> + report->outblob = NULL;
> >>> + report->auxblob = NULL;
> >>> + rc = ops->report_new(report, provider.data);
> >>
> >>
> >> Drop @ops and use "provider.ops" here?
> >
> > Shrug, ok.
>
> I asked as at first I thought it is stored right after rwsem_write in
> @ops for a reason but then it was not even checked for NULL so it could
> be initialized where declared.
I went back to declaring an @ops variable because this sequence needs to
validate that the ops are non-NULL under the lock, and typing
provider.ops several times is a bit grating.
/* slow path, report may need to be regenerated... */
guard(rwsem_write)(&tsm_rwsem);
ops = provider.ops;
if (!ops)
return -ENOTTY;
next prev parent reply other threads:[~2023-10-19 20:24 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-13 2:13 [PATCH v6 0/7] configfs-tsm: Attestation Report ABI Dan Williams
2023-10-13 2:14 ` [PATCH v6 1/7] virt: sevguest: Fix passing a stack buffer as a scatterlist target Dan Williams
2023-10-13 2:14 ` [PATCH v6 2/7] virt: coco: Add a coco/Makefile and coco/Kconfig Dan Williams
2023-10-13 2:14 ` [PATCH v6 3/7] configfs-tsm: Introduce a shared ABI for attestation reports Dan Williams
2023-10-13 4:43 ` Dionna Amalie Glaze
2023-10-13 5:15 ` Dan Williams
2023-10-16 6:36 ` Alexey Kardashevskiy
2023-10-17 2:19 ` Dan Williams
2023-10-17 6:20 ` Alexey Kardashevskiy
2023-10-19 1:29 ` Dan Williams
2023-10-19 20:24 ` Dan Williams [this message]
2023-10-13 2:14 ` [PATCH v6 4/7] virt: sevguest: Prep for kernel internal get_ext_report() Dan Williams
2023-10-13 2:14 ` [PATCH v6 5/7] mm/slab: Add __free() support for kvfree Dan Williams
2023-10-13 2:14 ` [PATCH v6 6/7] virt: sevguest: Add TSM_REPORTS support for SNP_GET_EXT_REPORT Dan Williams
2023-10-13 15:38 ` Tom Lendacky
2023-10-14 4:46 ` Dan Williams
2023-10-16 11:36 ` Alexey Kardashevskiy
2023-10-16 15:39 ` Dionna Amalie Glaze
2023-10-16 15:42 ` Peter Gonda
2023-10-17 0:42 ` Alexey Kardashevskiy
2023-10-19 4:30 ` Dan Williams
2023-10-17 4:07 ` Dan Williams
2023-10-17 5:35 ` Alexey Kardashevskiy
2023-10-17 6:28 ` Alexey Kardashevskiy
2023-10-19 4:43 ` Dan Williams
2023-10-19 5:12 ` Alexey Kardashevskiy
2023-10-19 3:34 ` Dan Williams
2023-10-13 2:14 ` [PATCH v6 7/7] virt: tdx-guest: Add Quote generation support using TSM_REPORTS Dan Williams
2023-10-19 18:12 ` Peter Gonda
2023-10-13 15:39 ` [PATCH v6 0/7] configfs-tsm: Attestation Report ABI Tom Lendacky
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