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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6BFA7C43219 for ; Tue, 10 May 2022 13:48:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244630AbiEJNvF (ORCPT ); Tue, 10 May 2022 09:51:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47176 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245479AbiEJNrp (ORCPT ); Tue, 10 May 2022 09:47:45 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 99A574AE23; Tue, 10 May 2022 06:35:50 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D4467B81DA2; Tue, 10 May 2022 13:35:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2072EC385A6; Tue, 10 May 2022 13:35:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652189747; bh=8afKrTcSFrOsl6NLq2WePN47DZBqol78HM8qqa1Bh2U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t19MfabBluxsyo94hTsXlMns3FfnlLfUxfSLCt05k2OiSCNscsoiX2xuL0fcr71Wq SVzXGqjRJAIFB8I1tVMfJiu5ZniTwgNdlVRzczUITJ0CnWs2vQHEXX2ws6zhQzDC4a oCupf7MSjdYAQcKHnUl+RT1o0ssAkRFAhOGN487k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Stevens , Kevin Tian , Lu Baolu , Joerg Roedel Subject: [PATCH 5.17 016/140] iommu/vt-d: Calculate mask for non-aligned flushes Date: Tue, 10 May 2022 15:06:46 +0200 Message-Id: <20220510130742.070972532@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220510130741.600270947@linuxfoundation.org> References: <20220510130741.600270947@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: David Stevens commit 59bf3557cf2f8a469a554aea1e3d2c8e72a579f7 upstream. Calculate the appropriate mask for non-size-aligned page selective invalidation. Since psi uses the mask value to mask out the lower order bits of the target address, properly flushing the iotlb requires using a mask value such that [pfn, pfn+pages) all lie within the flushed size-aligned region. This is not normally an issue because iova.c always allocates iovas that are aligned to their size. However, iovas which come from other sources (e.g. userspace via VFIO) may not be aligned. To properly flush the IOTLB, both the start and end pfns need to be equal after applying the mask. That means that the most efficient mask to use is the index of the lowest bit that is equal where all higher bits are also equal. For example, if pfn=0x17f and pages=3, then end_pfn=0x181, so the smallest mask we can use is 8. Any differences above the highest bit of pages are due to carrying, so by xnor'ing pfn and end_pfn and then masking out the lower order bits based on pages, we get 0xffffff00, where the first set bit is the mask we want to use. Fixes: 6fe1010d6d9c ("vfio/type1: DMA unmap chunking") Cc: stable@vger.kernel.org Signed-off-by: David Stevens Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/20220401022430.1262215-1-stevensd@google.com Signed-off-by: Lu Baolu Link: https://lore.kernel.org/r/20220410013533.3959168-2-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel Signed-off-by: Greg Kroah-Hartman --- drivers/iommu/intel/iommu.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -1717,7 +1717,8 @@ static void iommu_flush_iotlb_psi(struct unsigned long pfn, unsigned int pages, int ih, int map) { - unsigned int mask = ilog2(__roundup_pow_of_two(pages)); + unsigned int aligned_pages = __roundup_pow_of_two(pages); + unsigned int mask = ilog2(aligned_pages); uint64_t addr = (uint64_t)pfn << VTD_PAGE_SHIFT; u16 did = domain->iommu_did[iommu->seq_id]; @@ -1729,10 +1730,30 @@ static void iommu_flush_iotlb_psi(struct if (domain_use_first_level(domain)) { domain_flush_piotlb(iommu, domain, addr, pages, ih); } else { + unsigned long bitmask = aligned_pages - 1; + + /* + * PSI masks the low order bits of the base address. If the + * address isn't aligned to the mask, then compute a mask value + * needed to ensure the target range is flushed. + */ + if (unlikely(bitmask & pfn)) { + unsigned long end_pfn = pfn + pages - 1, shared_bits; + + /* + * Since end_pfn <= pfn + bitmask, the only way bits + * higher than bitmask can differ in pfn and end_pfn is + * by carrying. This means after masking out bitmask, + * high bits starting with the first set bit in + * shared_bits are all equal in both pfn and end_pfn. + */ + shared_bits = ~(pfn ^ end_pfn) & ~bitmask; + mask = shared_bits ? __ffs(shared_bits) : BITS_PER_LONG; + } + /* * Fallback to domain selective flush if no PSI support or - * the size is too big. PSI requires page size to be 2 ^ x, - * and the base address is naturally aligned to the size. + * the size is too big. */ if (!cap_pgsel_inv(iommu->cap) || mask > cap_max_amask_val(iommu->cap))