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From: Peter Zijlstra <peterz@infradead.org>
To: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Alexander Potapenko <glider@google.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
	syzbot+ffb4f000dc2872c93f62@syzkaller.appspotmail.com,
	syzbot+8cdd16fd5a6c0565e227@syzkaller.appspotmail.com
Subject: Re: [PATCH v2 5/5] x86/kasan: Populate shadow for shared chunk of the CPU entry area
Date: Mon, 14 Nov 2022 16:12:31 +0100	[thread overview]
Message-ID: <Y3Ja33LyShqjvmQZ@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <3b7a841d-bbbd-6018-556f-d2414a5f02b2@gmail.com>

On Mon, Nov 14, 2022 at 05:44:00PM +0300, Andrey Ryabinin wrote:
> Going back kasan_populate_shadow() seems like safer and easier choice.
> The only disadvantage of it that we might waste 1 page, which is not
> much compared to the KASAN memory overhead.

So the below delta?

---
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -388,7 +388,7 @@ void __init kasan_init(void)
 	shadow_cea_end = kasan_mem_to_shadow_align_up(CPU_ENTRY_AREA_BASE +
 						      CPU_ENTRY_AREA_MAP_SIZE);
 
-	kasan_populate_early_shadow(
+	kasan_populate_shadow(
 		kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM),
 		kasan_mem_to_shadow((void *)VMALLOC_START));
 

  reply	other threads:[~2022-11-14 17:39 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-10 20:34 [PATCH v2 0/5] x86/kasan: Bug fixes for recent CEA changes Sean Christopherson
2022-11-10 20:35 ` [PATCH v2 1/5] x86/mm: Recompute physical address for every page of per-CPU CEA mapping Sean Christopherson
2022-11-14 14:09   ` Andrey Ryabinin
2022-11-15 22:26   ` [tip: x86/mm] " tip-bot2 for Sean Christopherson
2022-12-17 18:55   ` tip-bot2 for Sean Christopherson
2022-11-10 20:35 ` [PATCH v2 2/5] x86/mm: Populate KASAN shadow for entire per-CPU range of CPU entry area Sean Christopherson
2022-11-14 14:10   ` Andrey Ryabinin
2022-11-15 22:26   ` [tip: x86/mm] " tip-bot2 for Sean Christopherson
2022-12-17 18:55   ` tip-bot2 for Sean Christopherson
2022-11-10 20:35 ` [PATCH v2 3/5] x86/kasan: Rename local CPU_ENTRY_AREA variables to shorten names Sean Christopherson
2022-11-14 14:10   ` Andrey Ryabinin
2022-11-15 22:26   ` [tip: x86/mm] " tip-bot2 for Sean Christopherson
2022-12-17 18:55   ` tip-bot2 for Sean Christopherson
2022-11-10 20:35 ` [PATCH v2 4/5] x86/kasan: Add helpers to align shadow addresses up and down Sean Christopherson
2022-11-14 14:13   ` Andrey Ryabinin
2022-11-15 22:26   ` [tip: x86/mm] " tip-bot2 for Sean Christopherson
2022-12-17 18:55   ` tip-bot2 for Sean Christopherson
2022-11-10 20:35 ` [PATCH v2 5/5] x86/kasan: Populate shadow for shared chunk of the CPU entry area Sean Christopherson
2022-11-14 14:44   ` Andrey Ryabinin
2022-11-14 15:12     ` Peter Zijlstra [this message]
2022-11-14 17:53       ` Sean Christopherson
2022-11-14 21:46         ` Peter Zijlstra
2022-11-15 22:26   ` [tip: x86/mm] " tip-bot2 for Sean Christopherson
2022-12-17 18:55   ` tip-bot2 for Sean Christopherson
2022-11-14 11:57 ` [PATCH v2 0/5] x86/kasan: Bug fixes for recent CEA changes Peter Zijlstra

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