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[46.102.197.194]) by smtp.gmail.com with ESMTPSA id fw16-20020a170906c95000b00a449b175d2fsm3420559ejb.222.2024.03.04.03.42.03 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 04 Mar 2024 03:42:04 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 392090a8-da1c-11ee-a1ee-f123f15fe8a2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloud.com; s=cloud; t=1709552524; x=1710157324; darn=lists.xenproject.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=snfhScXYKNnKUoeQj74fH7B2eTQCxeRrJzY3E9lPG5M=; b=LPJXjKuc2nLmshPswClNhJFd7P1OJuDV+Sd0/na2eMiHkm5pdsCMxx1JH5Sxyk2N2O kdBUQG+qhxh6oqOIkVKwKFThvjwEXAO7ssOXyGF+wWD8d04UYR8679F5oURyxjt7nKzK H4F0jTg1TTPFywlkTJmixeBbstcJn0BF2vPUc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709552524; x=1710157324; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=snfhScXYKNnKUoeQj74fH7B2eTQCxeRrJzY3E9lPG5M=; b=fhZr1OKohoqFQyORhic/vaNqZ6LCpeo64cbhsCnt2OCHNfyKQKvCE0zZsuRNVGhg1Z 5SXTcYrZQ7/HLQg94qZiAH+QFmHKhT6XLZqRBetLwNveayg1UfVF238CHErz3uMgoAFF nIWbfYGNnDjehnABlLvc9z5BANDGOqQh4xkxS7diB0UxAWAe3ixxYH5+6DTiSImK6c84 K7sXDri39ufkh74mzXM2czxmLpUkTK3g1FL1Ikl8U6rkviJbI2jB5Fjlk2s3OCCrhUog hZ40rm6YJo184GRLNPontLfe1NYDxV131c5ejJg/MVvyIzWmRL+g2WWoRB2iO6PKAO4o 4SMA== X-Forwarded-Encrypted: i=1; AJvYcCUA4VOIu7Esq138Rggr9FkJ0J2Sd4k0jfe8tCeInFiFLItT/mqCfu8BxPnCqz4Hn7k4J2/90iWwYbQpeelk83ClO3lFq1wBbwzehXkERdU= X-Gm-Message-State: AOJu0YwOwMo5uhvQv5+c1X70t+PuqlxMG9bknNgrXT7edVM14vyiCEHq 0RSVjpVMtfrYd/i9r8LbtxSODkOc0x8ypcsXdcUF+duDF8WCT+KSxZyWG5lr6/A= X-Google-Smtp-Source: AGHT+IFIkWbvxXqzrH9jBqABTlJqL63Uv/BugjsWwGTjPYFdDGbr5WM7ciRrcJjTFfDy525KTkhg0Q== X-Received: by 2002:a17:906:cc93:b0:a43:e46b:7a80 with SMTP id oq19-20020a170906cc9300b00a43e46b7a80mr5478341ejb.43.1709552524419; Mon, 04 Mar 2024 03:42:04 -0800 (PST) Message-ID: <70fcb88b-43d0-46e1-9d67-1f8a5d89f4f6@cloud.com> Date: Mon, 4 Mar 2024 11:42:01 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] hvmloader/PCI: skip huge BARs in certain calculations Content-Language: en-GB To: Jan Beulich , "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , Wei Liu , =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= , Neowutran References: <090d572c-5196-46b2-9d6b-741b7cb66d97@suse.com> From: Alejandro Vallejo In-Reply-To: <090d572c-5196-46b2-9d6b-741b7cb66d97@suse.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi, On 04/03/2024 07:32, Jan Beulich wrote: > BARs of size 2Gb and up can't possibly fit below 4Gb: Both the bottom of > the lower 2Gb range and the top of the higher 2Gb range have special > purpose. Don't even have them influence whether to (perhaps) relocate > low RAM. > > Reported-by: Neowutran > Signed-off-by: Jan Beulich > --- > If we wanted to fit e.g. multiple 1Gb BARs, it would likely be prudent > to similarly avoid low RAM relocation in the first place. Yet accounting > for things differently depending on how many large BARs there are would > require more intrusive code changes.> > That said, I'm open to further lowering of the threshold. That'll > require different justification then, though. > GPUs without resizable BARs tend to expose 256MiB on the BAR regardless of the amount of internal VRAM, AFAIK. So IMO 256 MiB is not a totally unmotivated number. I don't know which other PCIe devices might expose such big BARs for comparison. Cheers, Alejandro