From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5ED13C02194 for ; Thu, 6 Feb 2025 13:06:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=kuimryCjZ2Ztqx7vxfPlkW5S79f/2oVyGI8EiyfQHMM=; b=Rx5CzRASTjLwAqmwx6nSk9PYuD ZSmHbrzNhdf52QumhOwFMwEt1kGChc/J2sIZKrzAQPPlZKLc2O6sw6lf7fZeyAOHLS2YfT1/GU8XC broix1vGnW/XE0PG0U0AnUP0Xqi/zIK57MpkBUGSqXL3sG6B385fuFPdwXjrIFsQiQVCKxgQcuyTn dCPRlAhwjg9Z2bXe84qyq1M885HLJLQqyvkJR5mKOSBQZBzoiqzEsPMHZbmkAt4OV1/eYVpjvfz0E 6vSF3M1yF5wM/+LAkZmjMxB4JnoYmwVs17E/GIdT/wiaQVPyE+NivfgmiD72lq2Qycn6HaWIfjf4s NHEWbfhg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tg1a6-00000006LdD-3t63; Thu, 06 Feb 2025 13:06:10 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tg1Yj-00000006LKL-14ft for linux-arm-kernel@lists.infradead.org; Thu, 06 Feb 2025 13:04:46 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D6213FEC; Thu, 6 Feb 2025 05:05:07 -0800 (PST) Received: from [10.57.80.166] (unknown [10.57.80.166]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D4A733F5A1; Thu, 6 Feb 2025 05:04:41 -0800 (PST) Message-ID: Date: Thu, 6 Feb 2025 13:04:40 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 03/16] arm64: hugetlb: Fix flush_hugetlb_tlb_range() invalidation level Content-Language: en-GB To: Anshuman Khandual , Catalin Marinas , Will Deacon , Muchun Song , Pasha Tatashin , Andrew Morton , Uladzislau Rezki , Christoph Hellwig , Mark Rutland , Ard Biesheuvel , Dev Jain , Alexandre Ghiti , Steve Capper , Kevin Brodsky Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20250205151003.88959-1-ryan.roberts@arm.com> <20250205151003.88959-4-ryan.roberts@arm.com> From: Ryan Roberts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250206_050445_382575_EB118D3B X-CRM114-Status: GOOD ( 18.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 06/02/2025 06:46, Anshuman Khandual wrote: > > > On 2/5/25 20:39, Ryan Roberts wrote: >> commit c910f2b65518 ("arm64/mm: Update tlb invalidation routines for >> FEAT_LPA2") changed the "invalidation level unknown" hint from 0 to >> TLBI_TTL_UNKNOWN (INT_MAX). But the fallback "unknown level" path in >> flush_hugetlb_tlb_range() was not updated. So as it stands, when trying >> to invalidate CONT_PMD_SIZE or CONT_PTE_SIZE hugetlb mappings, we will >> spuriously try to invalidate at level 0 on LPA2-enabled systems. >> >> Fix this so that the fallback passes TLBI_TTL_UNKNOWN, and while we are >> at it, explicitly use the correct stride and level for CONT_PMD_SIZE and >> CONT_PTE_SIZE, which should provide a minor optimization. >> >> Cc: >> Fixes: c910f2b65518 ("arm64/mm: Update tlb invalidation routines for FEAT_LPA2") >> Signed-off-by: Ryan Roberts >> --- >> arch/arm64/include/asm/hugetlb.h | 20 ++++++++++++++------ >> 1 file changed, 14 insertions(+), 6 deletions(-) >> >> diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h >> index 03db9cb21ace..8ab9542d2d22 100644 >> --- a/arch/arm64/include/asm/hugetlb.h >> +++ b/arch/arm64/include/asm/hugetlb.h >> @@ -76,12 +76,20 @@ static inline void flush_hugetlb_tlb_range(struct vm_area_struct *vma, >> { >> unsigned long stride = huge_page_size(hstate_vma(vma)); >> >> - if (stride == PMD_SIZE) >> - __flush_tlb_range(vma, start, end, stride, false, 2); >> - else if (stride == PUD_SIZE) >> - __flush_tlb_range(vma, start, end, stride, false, 1); >> - else >> - __flush_tlb_range(vma, start, end, PAGE_SIZE, false, 0); >> + switch (stride) { >> + case PUD_SIZE: >> + __flush_tlb_range(vma, start, end, PUD_SIZE, false, 1); >> + break; > > Just wondering - should not !__PAGETABLE_PMD_FOLDED and pud_sect_supported() > checks also be added here for this PUD_SIZE case ? Yeah I guess so. TBH, it's never been entirely clear to me what the benefit is? Is it just to remove (a tiny amount of) dead code when we know we don't support blocks at the level? Or is there something more fundamental going on that I've missed? We seem to be quite inconsistent with the use of pud_sect_supported() in hugetlbpage.c. Anyway, I'll add this in, I guess it's preferable to follow the established pattern. Thanks, Ryan > >> + case CONT_PMD_SIZE: >> + case PMD_SIZE: >> + __flush_tlb_range(vma, start, end, PMD_SIZE, false, 2); >> + break; >> + case CONT_PTE_SIZE: >> + __flush_tlb_range(vma, start, end, PAGE_SIZE, false, 3); >> + break; >> + default: >> + __flush_tlb_range(vma, start, end, PAGE_SIZE, false, TLBI_TTL_UNKNOWN); >> + } >> } >> >> #endif /* __ASM_HUGETLB_H */