From: Andrew Banman <abanman@hpe.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirsky <luto@kernel.org>,
Dave Hansen <dave.hansen@intel.com>,
Borislav Petkov <bpetkov@suse.de>,
Greg KH <gregkh@linuxfoundation.org>,
keescook@google.com, hughd@google.com,
Brian Gerst <brgerst@gmail.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Denys Vlasenko <dvlasenk@redhat.com>,
Rik van Riel <riel@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
David Laight <David.Laight@aculab.com>,
Eduardo Valentin <eduval@amazon.com>,
aliguori@amazon.com, Will Deacon <will.deacon@arm.com>,
daniel.gruss@iaik.tugraz.at,
Dave Hansen <dave.hansen@linux.intel.com>,
Ingo Molnar <mingo@kernel.org>,
moritz.lipp@iaik.tugraz.at, linux-mm@kvack.org,
Borislav Petkov <bp@alien8.de>,
michael.schwarz@iaik.tugraz.at,
richard.fellner@student.tugraz.at,
Mike Travis <mike.travis@hpe.com>
Subject: Re: [PATCH 5/9] x86/uv: Use the right tlbflush API
Date: Tue, 5 Dec 2017 17:04:44 -0600 [thread overview]
Message-ID: <f5e07104-9262-851d-c8a3-7544653df9b6@hpe.com> (raw)
In-Reply-To: <20171205212727.GU3165@worktop.lehotels.local>
On 12/5/17 3:27 PM, Peter Zijlstra wrote:
> On Tue, Dec 05, 2017 at 03:09:48PM -0600, Andrew Banman wrote:
>> On 12/5/17 6:34 AM, Peter Zijlstra wrote:
>>> Since uv_flush_tlb_others() implements flush_tlb_others() which is
>>> about flushing user mappings, we should use __flush_tlb_single(),
>>> which too is about flushing user mappings.
>>>
>>> Cc: Andrew Banman<abanman@hpe.com>
>>> Cc: Mike Travis<mike.travis@hpe.com>
>>> Signed-off-by: Peter Zijlstra (Intel)<peterz@infradead.org>
>>> ---
>>> arch/x86/platform/uv/tlb_uv.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> --- a/arch/x86/platform/uv/tlb_uv.c
>>> +++ b/arch/x86/platform/uv/tlb_uv.c
>>> @@ -299,7 +299,7 @@ static void bau_process_message(struct m
>>> local_flush_tlb();
>>> stat->d_alltlb++;
>>> } else {
>>> - __flush_tlb_one(msg->address);
>>> + __flush_tlb_single(msg->address);
>>> stat->d_onetlb++;
>>> }
>>> stat->d_requestee++;
>>
>> This looks like the right thing to do. We'll be testing it and complain later if
>> we find any problems, but I'm not expecting any since this patch looks to
>> maintain our status quo.
>
> Well, with KPTI (the-patch-set-formerly-known-as-kaiser), there will be
> a distinct difference between the two.
>
> With KPTI __flush_tlb_one() would end up invalidating all kernel
> mappings while __flush_tlb_single() will end up only invalidating the
> user mappings of the current mm.
>
Right! Now the KPTI __flush_tlb_single() equals the old
__flush_tlb_one(), less the call to count_vm_tlb_event().
ACK
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next prev parent reply other threads:[~2017-12-05 23:04 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-05 12:34 [PATCH 0/9] Clarify/cleanup/fix tlbflush API/usage Peter Zijlstra
2017-12-05 12:34 ` [PATCH 1/9] x86/mm: Remove superfluous barriers Peter Zijlstra
2017-12-05 12:34 ` [PATCH 2/9] x86/mm: Create asm/invpcid.h Peter Zijlstra
2017-12-05 12:34 ` [PATCH 3/9] x86/mm: Address feedback Peter Zijlstra
2017-12-05 12:34 ` [PATCH 4/9] x86/mm: Use __flush_tlb_one() for kernel memory Peter Zijlstra
2017-12-05 12:34 ` [PATCH 5/9] x86/uv: Use the right tlbflush API Peter Zijlstra
2017-12-05 21:09 ` Andrew Banman
2017-12-05 21:27 ` Peter Zijlstra
2017-12-05 23:04 ` Andrew Banman [this message]
2017-12-05 12:34 ` [PATCH 6/9] x86/microcode: Dont abuse the tlbflush interface Peter Zijlstra
2017-12-05 12:34 ` [PATCH 7/9] x86/mm: Clarify which functions are supposed to flush what Peter Zijlstra
2017-12-05 12:34 ` [PATCH 8/9] x86/mm: Clarify the whole ASID/kernel PCID/user PCID naming Peter Zijlstra
2017-12-05 12:34 ` [PATCH 9/9] x86/doc: Remove obvious weirdness Peter Zijlstra
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