From: Jason Gunthorpe <jgg@nvidia.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Jacob Pan <jacob.jun.pan@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Ashok Raj <ashok_raj@linux.intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
x86@kernel.org, Kostya Serebryany <kcc@google.com>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Alexander Potapenko <glider@google.com>,
Taras Madan <tarasmadan@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
"H . J . Lu" <hjl.tools@gmail.com>,
Andi Kleen <ak@linux.intel.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCHv8 00/11] Linear Address Masking enabling
Date: Tue, 20 Sep 2022 13:27:27 -0300 [thread overview]
Message-ID: <Yynp77km4SaHpe/3@nvidia.com> (raw)
In-Reply-To: <15741fdf-68b6-bd32-b0c2-63fde3bb0db2@intel.com>
On Tue, Sep 20, 2022 at 09:06:32AM -0700, Dave Hansen wrote:
> On 9/20/22 06:14, Jason Gunthorpe wrote:
> > For this I would rather have a function that queries the format of the
> > page table under the mm_struct and we have enum values like
> > INTEL_NORMAL and INTEL_LAM as possible values.
> >
> > The iommu driver will block incompatible page table formats, and when
> > it starts up it should assert something that blocks changing the
> > format.
>
> That doesn't sound too bad. Except, please don't call it a "page table
> format". The format of the page tables does not change with LAM. It's
> entirely how the CPU interprets addresses that changes.
Sure it does. The rules for how the page table is walked change. The
actual bits stored in memory might not be different, but that doesn't
mean the format didn't change. If it didn't change we wouldn't have an
incompatibility with the IOMMU HW walker.
> Oh, and please don't call things "INTEL_WHATEVER". It looks silly and
> confuses the heck out of people when a second CPU vendor needs to use
> the same code.
I don't mean something where a second CPU vendor would re-use the
code, I mean literally to specify the exact format of the page tables,
where each CPU and configuration can get its own code. eg "Intel
x86-64 format 5 level, no lam"
At the end of the day the iommu drivers need to know this information
so they can program the HW to walk the same tables.
Today it is all implicit that if you have an iommu driver then it can
make assumptions about the layout, but if we add an API we may as well
be a bit more explicit at the same time.
Jason
next prev parent reply other threads:[~2022-09-20 16:27 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-30 1:00 Kirill A. Shutemov
2022-08-30 1:00 ` [PATCHv8 01/11] x86/mm: Fix CR3_ADDR_MASK Kirill A. Shutemov
2022-08-30 1:00 ` [PATCHv8 02/11] x86: CPUID and CR3/CR4 flags for Linear Address Masking Kirill A. Shutemov
2022-08-30 1:00 ` [PATCHv8 03/11] mm: Pass down mm_struct to untagged_addr() Kirill A. Shutemov
2022-08-30 1:00 ` [PATCHv8 04/11] x86/mm: Handle LAM on context switch Kirill A. Shutemov
2022-08-30 1:00 ` [PATCHv8 05/11] x86/uaccess: Provide untagged_addr() and remove tags before address check Kirill A. Shutemov
2022-08-30 1:00 ` [PATCHv8 06/11] x86/mm: Provide arch_prctl() interface for LAM Kirill A. Shutemov
2022-08-30 1:01 ` [PATCHv8 07/11] x86: Expose untagging mask in /proc/$PID/arch_status Kirill A. Shutemov
2022-08-30 1:01 ` [PATCHv8 08/11] selftests/x86/lam: Add malloc and tag-bits test cases for linear-address masking Kirill A. Shutemov
2022-08-30 1:01 ` [PATCHv8 09/11] selftests/x86/lam: Add mmap and SYSCALL " Kirill A. Shutemov
2022-09-07 3:19 ` Robert Hoo
2022-09-09 11:24 ` Zhang, Weihong
2022-08-30 1:01 ` [PATCHv8 10/11] selftests/x86/lam: Add io_uring " Kirill A. Shutemov
2022-08-30 1:01 ` [PATCHv8 11/11] selftests/x86/lam: Add inherit " Kirill A. Shutemov
2022-09-01 17:45 ` [PATCHv8 00/11] Linear Address Masking enabling Ashok Raj
2022-09-04 0:39 ` Kirill A. Shutemov
2022-09-09 16:08 ` Ashok Raj
2022-09-12 20:39 ` Jacob Pan
2022-09-12 21:41 ` Dave Hansen
2022-09-12 22:55 ` Jacob Pan
2022-09-13 0:06 ` Kirill A. Shutemov
2022-09-13 0:23 ` Ashok Raj
2022-09-12 22:49 ` Kirill A. Shutemov
2022-09-13 0:08 ` Jacob Pan
2022-09-13 0:18 ` Kirill A. Shutemov
2022-09-14 14:45 ` Kirill A. Shutemov
2022-09-14 15:11 ` Ashok Raj
2022-09-14 15:18 ` Kirill A. Shutemov
2022-09-14 15:31 ` Ashok Raj
2022-09-14 15:45 ` Kirill A. Shutemov
2022-09-14 23:51 ` Jacob Pan
2022-09-15 9:01 ` Kirill A. Shutemov
2022-09-15 17:28 ` Kirill A. Shutemov
2022-09-20 13:14 ` Jason Gunthorpe
2022-09-20 14:57 ` Ashok Raj
2022-09-20 16:06 ` Dave Hansen
2022-09-20 16:27 ` Jason Gunthorpe [this message]
2022-09-20 18:41 ` Jacob Pan
2022-09-20 18:50 ` Jason Gunthorpe
2022-09-20 20:44 ` Jacob Pan
2022-09-21 0:01 ` Jason Gunthorpe
2022-09-21 9:36 ` Tian, Kevin
2022-09-21 16:57 ` Dave Hansen
2022-09-21 17:08 ` Ashok Raj
2022-09-21 17:11 ` Dave Hansen
2022-09-21 17:29 ` Ashok Raj
2022-09-21 18:11 ` Jason Gunthorpe
2022-09-23 0:42 ` Kirill A. Shutemov
2022-09-23 5:27 ` Ashok Raj
2022-09-23 9:38 ` Kirill A. Shutemov
2022-09-23 11:46 ` Jason Gunthorpe
2022-09-23 14:18 ` Dave Hansen
2022-09-23 14:42 ` Jason Gunthorpe
2022-09-23 14:59 ` Ashok Raj
2022-09-23 15:28 ` Ashok Raj
2022-09-23 15:31 ` Dave Hansen
2022-09-23 15:44 ` Ashok Raj
2022-09-23 16:23 ` Dave Hansen
2022-09-23 16:44 ` Jason Gunthorpe
2022-09-04 1:00 ` Kirill A. Shutemov
2022-09-05 5:05 ` Bharata B Rao
2022-09-05 13:44 ` Kirill A. Shutemov
2022-09-05 14:30 ` Peter Zijlstra
2022-09-05 15:35 ` Kirill A. Shutemov
2022-09-05 15:46 ` Peter Zijlstra
2022-09-05 16:47 ` Kirill A. Shutemov
2022-09-06 8:39 ` Peter Zijlstra
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