From: Jason Gunthorpe <jgg@ziepe.ca>
To: Joonwon Kang <joonwonkang@google.com>
Cc: will@kernel.org, robin.murphy@arm.com, joro@8bytes.org,
jpb@kernel.org, Alexander.Grest@microsoft.com,
amhetre@nvidia.com, baolu.lu@linux.intel.com,
easwar.hariharan@linux.microsoft.com,
jacob.jun.pan@linux.intel.com, kees@kernel.org,
kevin.tian@intel.com, nicolinc@nvidia.com, praan@google.com,
smostafa@google.com, tglx@kernel.org, mingo@redhat.com,
bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org,
hpa@zytor.com, peterz@infradead.org, sohil.mehta@intel.com,
kas@kernel.org, alexander.shishkin@linux.intel.com,
ryasuoka@redhat.com, xin@zytor.com, linux-kernel@vger.kernel.org,
iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] iommu: Allow device driver to use its own PASID space for SVA
Date: Fri, 15 May 2026 20:18:08 -0300 [thread overview]
Message-ID: <20260515231808.GQ7702@ziepe.ca> (raw)
In-Reply-To: <20260515094605.3195841-1-joonwonkang@google.com>
On Fri, May 15, 2026 at 09:46:05AM +0000, Joonwon Kang wrote:
> diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
> index 0ca3912ecb7f..61e2e52105e5 100644
> --- a/arch/x86/kernel/traps.c
> +++ b/arch/x86/kernel/traps.c
> @@ -864,6 +864,8 @@ static bool try_fixup_enqcmd_gp(void)
> return false;
>
> pasid = mm_get_enqcmd_pasid(current->mm);
> + if (pasid == IOMMU_PASID_INVALID)
> + return false;
If you do this then probably you should get rid of mm_valid_pasid(),
mm_get_enqcmd_pasid() already has the NULL check so the two functions
are kind of pointless.
You also missed the other place calling mm_valid_pasid() that should
really be sensitive to this as well:
static int prctl_enable_tagged_addr(struct mm_struct *mm, unsigned long nr_bits)
{
[..]
if (mm_valid_pasid(mm) &&
!test_bit(MM_CONTEXT_FORCE_TAGGED_SVA, &mm->context.flags))
return -EINVAL;
Make that removal a prep patch
I didn't try to check the rest closely but the approach looked sane to
me
Jason
prev parent reply other threads:[~2026-05-15 23:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-15 9:46 [PATCH] iommu: Allow device driver to use its own PASID space for SVA Joonwon Kang
2026-05-15 23:18 ` Jason Gunthorpe [this message]
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