From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1A20940244D for ; Tue, 21 Jul 2026 17:28:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784654937; cv=none; b=QaxYBOZiKO2vyJeYNvQGZzKNLAr2hP5NK8UpP786JvjKLreO9aBrDLXxKmgb4EKryQ3ZX4bQhuIUDDhECAyABz4gLL2M4+A3FJ2ZVhONBRlNfamaP1/hqPfaNqPWCKhZ4KMerbalN9Pu5AduBFySSm4d/bOWo6I7vn+5X/lXU1Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784654937; c=relaxed/simple; bh=WyqRoPXsVrHKdwl2J9XFk7p6M3EBXDqAvDpsBZP0XW0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Hf/8/D5GBCZs8ELdaC025pZd7f6tn/TyUwNsAMrN5I7mRMnwj91RbnoyzAolspw+VhH0EwsJ5ji2jj/v6KI5WaMEk8CApfc0NYBt3yyMwUDWs61Z6zLkWnouyKYgtv013oL3VG5agR0xaFYQlkUJCgq9YoETZgm8AEF+yY35Lms= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kO8otqz4; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kO8otqz4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BABD31F00A3A; Tue, 21 Jul 2026 17:28:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784654935; bh=YiQsLKvFG9y9z6ojkxTZaOd0u2J+iHl4tP+F1/26nzo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kO8otqz4upxMoOPrxv2KBFc0S/3pLzCPUBt+dsERvOn1iuX1sA42Nn+Ws7QPaDxeC Rzn57S2DcIN7A0kNejFuE7al0TzVciA/MngZbB7sd3Lr28WknQEyLIlfPHNae69v4x nvE2fBimqZrXJtir87UNRaywOKVigOdHrkTmwWkyyZtVzW93pqF2pub3SlWqP+KLPq JK5kXxjTGOJHTKWXJLZx+KO4sPZVOf6HCUJVBuJ3rz2eUn42HiGIROwiiuR/jVLDcR olJWTT49mOS5oaAHXLpfV28c8bNVX17NKsa7sb6kOXYwru79LVqnm7R+qx3JCJVeqa Q3Ae1qoAO8RBw== From: Sasha Levin To: stable@vger.kernel.org Cc: Weinan Liu , Josef Bacik , Jason Gunthorpe , Wei Wang , Samiullah Khawaja , Suravee Suthikulpanit , Vasant Hegde , Joerg Roedel , Sasha Levin Subject: [PATCH 5.15.y] iommu/amd: Don't split flush for amd_iommu_domain_flush_all() Date: Tue, 21 Jul 2026 13:28:53 -0400 Message-ID: <20260721172853.205813-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026071648-ogle-phonics-2909@gregkh> References: <2026071648-ogle-phonics-2909@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Weinan Liu [ Upstream commit 69fe699afe1afcb730164b86c228483c2da05f94 ] We have observed multiple full invalidations occurring during device detach when we are done using the vfio-device. blocked_domain_attach_device() -> detach_device() -> amd_iommu_domain_flush_all() -> amd_iommu_domain_flush_pages(..., CMD_INV_IOMMU_ALL_PAGES_ADDRESS) while (size != 0) { -> __domain_flush_pages( flush_size /* power of 2 flush_size */) -> domain_flush_pages_v1() -> build_inv_iommu_pages() -> build_inv_address() } build_inv_address() will trigger a full invalidation if the chunk size > (1 << 51). Consequently, the guest will issue multiple full invalidations for a single call to amd_iommu_domain_flush_all() Without this patch, we will see 10 time instead of 1 time full invalidations for every amd_iommu_domain_flush_all(). Cc: stable@vger.kernel.org Fixes: a270be1b3fdf ("iommu/amd: Use only natural aligned flushes in a VM") Suggested-by: Josef Bacik Suggested-by: Jason Gunthorpe Signed-off-by: Weinan Liu Reviewed-by: Wei Wang Reviewed-by: Jason Gunthorpe Reviewed-by: Samiullah Khawaja Reviewed-by: Suravee Suthikulpanit Reviewed-by: Vasant Hegde Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin --- drivers/iommu/amd/iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c index d3a11be8d1ddd3..b4e4f21fe2bed3 100644 --- a/drivers/iommu/amd/iommu.c +++ b/drivers/iommu/amd/iommu.c @@ -1284,7 +1284,8 @@ static void __domain_flush_pages(struct protection_domain *domain, static void domain_flush_pages(struct protection_domain *domain, u64 address, size_t size, int pde) { - if (likely(!amd_iommu_np_cache)) { + if (likely(!amd_iommu_np_cache) || + size >= (1ULL<<52)) { __domain_flush_pages(domain, address, size, pde); return; } -- 2.53.0