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[47.54.130.67]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8c90b2db7fbsm66749856d6.28.2026.05.15.16.18.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 May 2026 16:18:09 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1wO1nF-00000008IBY-019X; Fri, 15 May 2026 20:18:09 -0300 Date: Fri, 15 May 2026 20:18:08 -0300 From: Jason Gunthorpe To: Joonwon Kang 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 Message-ID: <20260515231808.GQ7702@ziepe.ca> References: <20260515094605.3195841-1-joonwonkang@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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