From: Jason Gunthorpe <jgg@nvidia.com>
To: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
joro@8bytes.org, robin.murphy@arm.com, vasant.hegde@amd.com,
kevin.tian@intel.com, jon.grimm@amd.com, santosh.shukla@amd.com,
pandoh@google.com, kumaranand@google.com
Subject: Re: [PATCH v8 06/10] iommu/amd: Modify set_dte_entry() to use 256-bit DTE helpers
Date: Fri, 1 Nov 2024 09:10:22 -0300 [thread overview]
Message-ID: <20241101121022.GT10193@nvidia.com> (raw)
In-Reply-To: <20241031184243.4184-7-suravee.suthikulpanit@amd.com>
On Thu, Oct 31, 2024 at 06:42:39PM +0000, Suravee Suthikulpanit wrote:
> +struct dev_table_entry *amd_iommu_get_ivhd_dte_flags(u16 segid, u16 devid)
> +{
> + struct ivhd_dte_flags *e;
> + unsigned int best_len = UINT_MAX;
> + struct dev_table_entry *dte = NULL;
> +
> + for_each_ivhd_dte_flags(e) {
> + /*
> + * Need to go through the whole list to find the smallest range,
> + * which contains the devid.
> + */
> + if ((e->segid == segid) &&
> + (e->devid_first >= devid) &&
> + (e->devid_last <= devid)) {
Again, I don't know much about this format, but are you sure about
this logic? Consider:
e->devid_first = 10
devid = 12
e->devid_last = 15
(e->devid_first >= devid) == 10 >= 12 == FALSE
(e->devid_last <= devid) == 15 <= 12 == FALSE
FALSE && FALSE == FALSE
It seems to me it does not do what the comment says? Compare to the
version I sent in my last email
Jason
next prev parent reply other threads:[~2024-11-01 12:10 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-31 18:42 [PATCH v8 00/10] iommu/amd: Use 128-bit cmpxchg operation to update DTE Suravee Suthikulpanit
2024-10-31 18:42 ` [PATCH v8 01/10] iommu/amd: Misc ACPI IVRS debug info clean up Suravee Suthikulpanit
2024-10-31 18:42 ` [PATCH v8 02/10] iommu/amd: Disable AMD IOMMU if CMPXCHG16B feature is not supported Suravee Suthikulpanit
2024-10-31 18:42 ` [PATCH v8 03/10] asm/rwonce: Introduce [READ|WRITE]_ONCE() support for __int128 Suravee Suthikulpanit
2024-10-31 18:42 ` [PATCH v8 04/10] iommu/amd: Introduce struct ivhd_dte_flags to store persistent DTE flags Suravee Suthikulpanit
2024-10-31 18:42 ` [PATCH v8 05/10] iommu/amd: Introduce helper function to update 256-bit DTE Suravee Suthikulpanit
2024-10-31 18:42 ` [PATCH v8 06/10] iommu/amd: Modify set_dte_entry() to use 256-bit DTE helpers Suravee Suthikulpanit
2024-11-01 12:10 ` Jason Gunthorpe [this message]
2024-11-01 15:02 ` Suthikulpanit, Suravee
2024-10-31 18:42 ` [PATCH v8 07/10] iommu/amd: Introduce helper function get_dte256() Suravee Suthikulpanit
2024-10-31 18:42 ` [PATCH v8 08/10] iommu/amd: Modify clear_dte_entry() to avoid in-place update Suravee Suthikulpanit
2024-10-31 18:42 ` [PATCH v8 09/10] iommu/amd: Lock DTE before updating the entry with WRITE_ONCE() Suravee Suthikulpanit
2024-10-31 18:42 ` [PATCH v8 10/10] iommu/amd: Remove amd_iommu_apply_erratum_63() Suravee Suthikulpanit
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