From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f171.google.com (mail-qt1-f171.google.com [209.85.160.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC96A1420D2 for ; Fri, 2 Feb 2024 15:30:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706887818; cv=none; b=oh+pC542VL8ISL+6l4+Ylhch0gXIhyIVPejfcza3q/XETVKqD+zM93wLQoa11PXy20an730yPbschVNt2KzKm3C6LtC7qmRYD9xkzb27jWcb+1K0hDQ5OdhkjSOChwWXj1Smj26aCpDqUG5PP1zyn4bx9iFDn6eNBGu1FjR4Fq4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706887818; c=relaxed/simple; bh=DIobH/pU80Zp7oCxEnbTAgh4qK5UveR6Ntsc6J70nh0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kjAg4B9TTKNsGP41RB8d77zvPyxeg9XbZXvwayktEqeTnptyCwnzWe0axMo/aC+3OweLTHwp9eSAYqzOAngw0ANA5MbiJSsvjxWNa1q9+cXPPmEp+ZKSrv83cWn37y7FgdXet2gRltWNaU3XodlVx28XUIoVwyEmuvczyqFOSfQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca; spf=pass smtp.mailfrom=ziepe.ca; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b=jBLxEc3l; arc=none smtp.client-ip=209.85.160.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="jBLxEc3l" Received: by mail-qt1-f171.google.com with SMTP id d75a77b69052e-42a8900bb93so16915541cf.1 for ; Fri, 02 Feb 2024 07:30:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1706887815; x=1707492615; darn=lists.linux.dev; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=FPiaOD3cBsyS5OjYUKhO9PRQyCvL9OaMbBqS+gF3xwA=; b=jBLxEc3lGmCDZWFYy47T9DDIqWTh5ULrienCsBlo8paTUx/f+YvZI0JNiLRGHs0Hzs 3ztSYq6O2fB55YcV30pjXbzQvo/q8XDKAY7mIjAmzuzrwb0cWNdRE3r9M1dkVfJbwIZJ OWpTTAXtLaZSy9bzp6RZk1f4509/VJ+qgpu0Vtd57EbHRlLfPAmuugIahl58bhaCQnkr Vdb/G+uTi+tZ7TBYBbYJlyYgqJtyKkCnV21vpDmjddnicMlqIcxQDt+R8DgR9h/XqvXn 7tkoniaNhn/p2ntcrYmTSNw7Yf4tf0r0yz0BmmAgX0WHDRsekPEUGMiFV5mX8+/+vdye AnDQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706887815; x=1707492615; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=FPiaOD3cBsyS5OjYUKhO9PRQyCvL9OaMbBqS+gF3xwA=; b=PK1QebY3y7EXA+wFEyNEdqr31fUg85cvoDOqELVvPx0M6K8xQ+3g7yrzRPK2wAxM8V OWPieIbjZfLWf1CsMJxrhsORX7V3747lr7kbACxZkolObi8K41OC96u8zqg0L4fn8zq5 01XlvpEv2HMy5IxxCCOFBUK23POvNM6qCk/h+t8mVlc+TmgLzSVXuWEz0+K6UEgGyCmO xhX/eGFQkSUR4GoFGTrRgkIA5VK+Xwg1rnxY0TQqwWBCUfmlsJ4UR0z3f+XSsYDjo/wG VlZMJuFWAu8Vh78AN2XAS1URn2nXMPKN91L8hfomSr7p1BzkpXs7JzvEFoeZIlo4vl6+ hhNA== X-Gm-Message-State: AOJu0YzFulIRSXOxekRYczZSJ13Jp9k4eiuYFWXGNrPkaGUPh1kwvuDM N15hCBvfn5N+ZgXPQ2xNrB5cnnnJkg3eX+3mpLSBuf7lHw9Em8DDJHovb+w9Npg= X-Google-Smtp-Source: AGHT+IF/HWsLZlcdZWPlR1pBa5IRrBpCqFicr6rA4MruYWS6d/ECTIuxsGN/kevPt1TlZHm4n+u8cQ== X-Received: by 2002:ac8:530c:0:b0:42c:840:7daa with SMTP id t12-20020ac8530c000000b0042c08407daamr841753qtn.27.1706887815725; Fri, 02 Feb 2024 07:30:15 -0800 (PST) X-Forwarded-Encrypted: i=0; AJvYcCUcp3h2M+KINmSgEaxTfCOnqiaX1FdbI4ZaLGwv5L3u4LNwI6W+BH/9imk5VwVSb8o+FUnzBspmfocx181Wx+PNEvxgGjookfIJyqFD2OEHZmEH7Dld047MYuf89AJQaI5W6OC5+ZSiCe+2bPafMdgXsOk4hnM+kE4i0hIouQeGuorg4Xpf+DnYxkbKnVXN8wSfq99Ok2GQUojE0qY45Za1 Received: from ziepe.ca (hlfxns017vw-142-68-80-239.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.68.80.239]) by smtp.gmail.com with ESMTPSA id w38-20020a05622a192600b0042ab85638fbsm916402qtc.44.2024.02.02.07.30.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Feb 2024 07:30:15 -0800 (PST) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1rVvUc-00AwEg-N9; Fri, 02 Feb 2024 11:30:14 -0400 Date: Fri, 2 Feb 2024 11:30:14 -0400 From: Jason Gunthorpe To: Vasant Hegde Cc: iommu@lists.linux.dev, joro@8bytes.org, suravee.suthikulpanit@amd.com, wei.huang2@amd.com, jsnitsel@redhat.com, Tom Lendacky Subject: Re: [PATCH v5 05/14] iommu/amd: Fix PPR interrupt processing logic Message-ID: <20240202153014.GY50608@ziepe.ca> References: <20240118073339.6978-1-vasant.hegde@amd.com> <20240118073339.6978-6-vasant.hegde@amd.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240118073339.6978-6-vasant.hegde@amd.com> On Thu, Jan 18, 2024 at 07:33:30AM +0000, Vasant Hegde wrote: > * Do not re-read ppr head pointer as its just updated by the driver. > > * Do not read PPR buffer tail pointer inside while loop. If IOMMU > generates PPR events continuously then completing interrupt processing > takes long time. In worst case it may cause infinite loop. > > Suggested-by: Tom Lendacky > Signed-off-by: Vasant Hegde > --- > drivers/iommu/amd/ppr.c | 4 ---- > 1 file changed, 4 deletions(-) Reviewed-by: Jason Gunthorpe Jason