> On Feb 7, 2019, at 2:53 PM, Linus Torvalds
> wrote:
>
>> On Thu, Feb 7, 2019 at 1:24 PM Andy Lutomirski wrote:
>>
>> How bad would it be to set CR0.CD while fiddling with the page tables rather
>> than masking the address?
>
> I would suggest against it. When you disable caching,
On Thu, Feb 7, 2019 at 1:24 PM Andy Lutomirski wrote:
>
> How bad would it be to set CR0.CD while fiddling with the page tables rather
> than masking the address?
I would suggest against it. When you disable caching, things don't
just go "slightly slower". Everything comes to a screeching halt,
> On Feb 7, 2019, at 10:46 AM, Luck, Tony wrote:
>
>> On Thu, Feb 07, 2019 at 10:07:28AM -0800, Andy Lutomirski wrote:
>> Joining this thread late...
>>
>> This is all IMO rather crazy. How about we fiddle with CR0 to turn off
>> the cache, then fiddle with page tables, then turn caching
On Thu, Feb 07, 2019 at 10:07:28AM -0800, Andy Lutomirski wrote:
> Joining this thread late...
>
> This is all IMO rather crazy. How about we fiddle with CR0 to turn off
> the cache, then fiddle with page tables, then turn caching on? Or, heck,
> see if there’s some chicken bit we can set to
On Thu, Feb 07, 2019 at 06:57:20PM +0100, Peter Zijlstra wrote:
> Something like so then? AFAICT CLFLUSH will also #GP if feed it crap.
Correct. CFLUSH will also #GP on a non-canonical address.
> - __flush_tlb_one_kernel(__cpa_addr(cpa, i));
> +
> On Feb 7, 2019, at 9:57 AM, Peter Zijlstra wrote:
>
>> On Thu, Feb 07, 2019 at 09:36:00AM -0800, Luck, Tony wrote:
>>> On Thu, Feb 07, 2019 at 03:01:31PM +0100, Peter Zijlstra wrote:
On Thu, Feb 07, 2019 at 11:50:52AM +, Linus Torvalds wrote:
If you re-generate the canonical
On Thu, Feb 07, 2019 at 09:36:00AM -0800, Luck, Tony wrote:
> On Thu, Feb 07, 2019 at 03:01:31PM +0100, Peter Zijlstra wrote:
> > On Thu, Feb 07, 2019 at 11:50:52AM +, Linus Torvalds wrote:
> > > If you re-generate the canonical address in __cpa_addr(), now we'll
> > > actually have the real
On Thu, Feb 07, 2019 at 03:01:31PM +0100, Peter Zijlstra wrote:
> On Thu, Feb 07, 2019 at 11:50:52AM +, Linus Torvalds wrote:
> > If you re-generate the canonical address in __cpa_addr(), now we'll
> > actually have the real virtual address around for a lot of code-paths
> > (pte lookup etc),
On Thu, Feb 07, 2019 at 11:50:52AM +, Linus Torvalds wrote:
> If you re-generate the canonical address in __cpa_addr(), now we'll
> actually have the real virtual address around for a lot of code-paths
> (pte lookup etc), which was what people wanted to avoid in the first
> place.
Note that
On Thu, Feb 7, 2019 at 10:18 AM Peter Zijlstra wrote:
>
> So now the question is where to put it back in, I'm thinking this might
> want to be in __cpa_addr().
Wasn't one of the goals to *not* keep the real virtual address around
to avoid speculation, since we don't want some random speculation
On Wed, Feb 06, 2019 at 04:17:42PM -0800, Luck, Tony wrote:
> fe0937b24ff5 ("x86/mm/cpa: Fold cpa_flush_range() and cpa_flush_array() into
> a single cpa_flush() function")
Boris pointed me at this gem:
c7486104a5ce ("x86/mce: Fix set_mce_nospec() to avoid #GP fault")
(can I just revel at
On Wed, Feb 06, 2019 at 04:33:54PM -0800, Dave Hansen wrote:
> I wonder if the patches that you bisected to just changed the flushing
> from being CR3-based (and not taking an address) to being INVPCID-based,
> and taking an address that is sensitive to canonicality.
That is indeed one of the
On 2/6/19 4:17 PM, Luck, Tony wrote:
> [ 93.491692] RAX: RBX: RCX:
> 99623f2c3f70
> [ 93.499658] RDX: 2e6b58da0121 RSI: RDI:
> 7fff9981feeab000
...
> Potentially the problem might be a non-canonical address passed down
> by the
On Tue, Dec 25, 2018 at 12:11:06AM +0100, Ingo Molnar wrote:
> Peter Zijlstra (9):
> x86/mm/cpa: Add ARRAY and PAGES_ARRAY selftests
> x86/mm/cpa: Add __cpa_addr() helper
> x86/mm/cpa: Make cpa_data::vaddr invariant
> x86/mm/cpa: Simplify the code after making cpa->vaddr
The pull request you sent on Tue, 25 Dec 2018 00:11:06 +0100:
> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-mm-for-linus
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/e57d9f638af9673f38d9f09de66fa0a28303127d
Thank you!
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