From: Thomas Gleixner <tglx@linutronix.de>
To: Fenghua Yu <fenghua.yu@intel.com>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Tony Luck <tony.luck@intel.com>,
Lu Baolu <baolu.lu@linux.intel.com>,
Joerg Roedel <joro@8bytes.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Ravi V Shankar <ravi.v.shankar@intel.com>
Cc: iommu@lists.linux-foundation.org, x86 <x86@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Fenghua Yu <fenghua.yu@intel.com>
Subject: Re: [PATCH v2 05/11] iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit
Date: Mon, 24 Jan 2022 21:21:24 +0100 [thread overview]
Message-ID: <87ee4w6g1n.ffs@tglx> (raw)
In-Reply-To: <20211217220136.2762116-6-fenghua.yu@intel.com>
On Fri, Dec 17 2021 at 22:01, Fenghua Yu wrote:
> diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c
> index bd41405d34e9..ee2294e02716 100644
> --- a/drivers/iommu/iommu-sva-lib.c
> +++ b/drivers/iommu/iommu-sva-lib.c
> @@ -18,8 +18,7 @@ static DECLARE_IOASID_SET(iommu_sva_pasid);
> *
> * Try to allocate a PASID for this mm, or take a reference to the existing one
> * provided it fits within the [@min, @max] range. On success the PASID is
> - * available in mm->pasid, and must be released with iommu_sva_free_pasid().
> - * @min must be greater than 0, because 0 indicates an unused mm->pasid.
> + * available in mm->pasid and will be available for the lifetime of the mm.
> *
> * Returns 0 on success and < 0 on error.
> */
> @@ -33,38 +32,24 @@ int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max)
> return -EINVAL;
>
> mutex_lock(&iommu_sva_lock);
> - if (mm->pasid) {
> - if (mm->pasid >= min && mm->pasid <= max)
> - ioasid_get(mm->pasid);
> - else
> + /* Is a PASID already associated with this mm? */
> + if (pasid_valid(mm->pasid)) {
> + if (mm->pasid < min || mm->pasid >= max)
> ret = -EOVERFLOW;
> - } else {
> - pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm);
> - if (pasid == INVALID_IOASID)
> - ret = -ENOMEM;
> - else
> - mm->pasid = pasid;
> + goto out;
> }
> +
> + pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm);
> + if (!pasid_valid(pasid))
> + ret = -ENOMEM;
> + else
> + mm_pasid_get(mm, pasid);
Hrm. This is odd.
> +/* Associate a PASID with an mm_struct: */
> +static inline void mm_pasid_get(struct mm_struct *mm, u32 pasid)
> +{
> + mm->pasid = pasid;
> +}
This does not get anything. It sets the allocated PASID in the mm. The
refcount on the PASID was already taken by the allocation. So this
should be mm_pasid_set() or mm_pasid_install(), right?
Thanks,
tglx
next prev parent reply other threads:[~2022-01-24 22:30 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-17 22:01 [PATCH v2 00/11] Re-enable ENQCMD and PASID MSR Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 01/11] iommu/sva: Rename CONFIG_IOMMU_SVA_LIB to CONFIG_IOMMU_SVA Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 02/11] mm: Change CONFIG option for mm->pasid field Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 03/11] iommu/ioasid: Introduce a helper to check for valid PASIDs Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 04/11] kernel/fork: Initialize mm's PASID Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 05/11] iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit Fenghua Yu
2022-01-24 20:21 ` Thomas Gleixner [this message]
2022-01-24 20:33 ` Fenghua Yu
2022-01-24 20:36 ` Thomas Gleixner
2022-01-24 20:52 ` Fenghua Yu
2022-01-24 20:55 ` Thomas Gleixner
2022-01-25 15:18 ` Fenghua Yu
2022-01-26 14:23 ` Thomas Gleixner
2022-01-26 17:36 ` Fenghua Yu
2022-01-26 21:38 ` Thomas Gleixner
2022-01-28 2:42 ` Fenghua Yu
2022-01-28 14:53 ` Thomas Gleixner
2021-12-17 22:01 ` [PATCH v2 06/11] x86/fpu: Clear PASID when copying fpstate Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 07/11] sched: Define and initialize a flag to identify valid PASID in the task Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 08/11] x86/traps: Demand-populate PASID MSR via #GP Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 09/11] x86/cpufeatures: Re-enable ENQCMD Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 10/11] tools/objtool: Check for use of the ENQCMD instruction in the kernel Fenghua Yu
2021-12-17 22:57 ` Josh Poimboeuf
2021-12-27 17:50 ` Fenghua Yu
2021-12-17 22:01 ` [PATCH v2 11/11] docs: x86: Change documentation for SVA (Shared Virtual Addressing) Fenghua Yu
2021-12-27 17:52 ` [PATCH v2 00/11] Re-enable ENQCMD and PASID MSR Fenghua Yu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87ee4w6g1n.ffs@tglx \
--to=tglx@linutronix.de \
--cc=ashok.raj@intel.com \
--cc=baolu.lu@linux.intel.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=fenghua.yu@intel.com \
--cc=iommu@lists.linux-foundation.org \
--cc=jacob.jun.pan@linux.intel.com \
--cc=joro@8bytes.org \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=ravi.v.shankar@intel.com \
--cc=tony.luck@intel.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).