From patchwork Thu Feb 20 22:40:32 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergio Lopez X-Patchwork-Id: 13984567 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 2E6E3C021B3 for ; Thu, 20 Feb 2025 22:41:27 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7770210E9ED; Thu, 20 Feb 2025 22:41:26 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="SOnwPIrf"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id EE63D10E9EF for ; Thu, 20 Feb 2025 22:41:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1740091284; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=x+F1eHhpCOtGRCps9D9sPa5vqYZpX8AGVB3hKqFOcK4=; b=SOnwPIrfGu2at3QvQyToEXk5YQfASUOSyfHDGPuEW6Q+2s1xuFpaEi1BGHB4F4fQxl3SAq TkoOAKwmI2Twrz7h9Yq/ttDOUbfvINELQNJWtuqH23e1r/uZhcgkznndNyMhQTjNq+J2Yc 3OXrsrVobY+cbrzgiWJal3i/GinZWHc= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-552-XiyJNyuFOnuNGvTbdyAzBg-1; Thu, 20 Feb 2025 17:41:20 -0500 X-MC-Unique: XiyJNyuFOnuNGvTbdyAzBg-1 X-Mimecast-MFC-AGG-ID: XiyJNyuFOnuNGvTbdyAzBg_1740091278 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9F7F21979057; Thu, 20 Feb 2025 22:41:17 +0000 (UTC) Received: from [127.0.1.1] (unknown [10.44.32.26]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 1CA6F1800359; Thu, 20 Feb 2025 22:41:09 +0000 (UTC) From: Sergio Lopez Date: Thu, 20 Feb 2025 23:40:32 +0100 Subject: [PATCH RFC v4 3/4] virtio-mmio: read shm region page size MIME-Version: 1.0 Message-Id: <20250220-virtio-shm-page-size-v4-3-ddaed7b6f734@redhat.com> References: <20250220-virtio-shm-page-size-v4-0-ddaed7b6f734@redhat.com> In-Reply-To: <20250220-virtio-shm-page-size-v4-0-ddaed7b6f734@redhat.com> To: "Michael S. Tsirkin" , Daniel Verkamp , Jason Wang , Xuan Zhuo , =?utf-8?q?Eugenio_P=C3=A9rez?= , David Airlie , Gerd Hoffmann , Gurchetan Singh , Chia-I Wu , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Simona Vetter , Rob Clark , Dmitry Osipenko , fnkl.kernel@gmail.com Cc: virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Sergio Lopez X-Developer-Signature: v=1; a=openpgp-sha256; l=2425; i=slp@redhat.com; h=from:subject:message-id; bh=Ehj8/j16O8eT/oyoXvssheCZbXxBfefe7YN3dkYS8pA=; b=owEBbQKS/ZANAwAIAfRpJ40vDAI1AcsmYgBnt69txYXyawKpopF3mRu4vuKWWmiWXOzHXeg8b dlMQo7n/g6JAjMEAAEIAB0WIQS+1fz3US2GgJFC6KL0aSeNLwwCNQUCZ7evbQAKCRD0aSeNLwwC Ne4cD/9Y14GppRUWfTPTUgZUvWhFCX3/t575waWpyGh3UONuPgsMzIRajm0Lrse4JWGg/SefzA3 2DC8qKFJJIx3HS8iaROUiGHLsSyiTe6n9bj5Me8dlK583tSJZ8KVpyUijwZXhRhQCvQX+EWSjjj 5dhsLhFW9x2rTlyO4MvB5iOg+Z5MUezx2ocpqZ90/9LCXD/w6hX75sOkbI3bOQVD4O6FUYRal6+ M1xDA0afOROOn3pCApNHw3ZWVkpNkllX0CxvpwpKChdnB33Uj/ZAkHwMnLHONrGMS800kokTS+O wOWf2vXGHOz2akaIEhqbSH3dh47Xer2qQWMyBWM35cksHqzCJgKA1AkcZSHX0h0aedPYg3ZGq9y 5Pj3crXk10uivWk8hudxf13Kaf1YAKoSEOOowTWz9A790vmjG4HlOpJpdRHkXC3SByLB+lyPWv9 mX95mD4vb8g6w+oNOJros1NmnId8NMwl01LVJ/gHHBmQCTWoTQXoFJgOGZONrsag1U6GCaqWhrr 9/2T26PdzOrwjwI3kMwj13yhe7neaNvgYwOuX8RtPFc7MqeNWwl6axXMVCsPmMMcC/c+aPeuL0D w4Ryz81KwoxNtQ0gJmsJ45HcQ3dPCvJ14Lu5HmAQvTeP+FqGqJMcmZ6rwpZ+L597nrRm3Nr6XWn PVlKyHMJVE/d0lA== X-Developer-Key: i=slp@redhat.com; a=openpgp; fpr=BED5FCF7512D86809142E8A2F469278D2F0C0235 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Use the newly introduced SHM_PAGE_SHIFT register to read the page shift for the shared memory region, derive the page size from it and store the resulting value into virtio_shm_region. Reviewed-by: Dmitry Osipenko Signed-off-by: Sergio Lopez --- drivers/virtio/virtio_mmio.c | 20 +++++++++++++++++++- include/uapi/linux/virtio_mmio.h | 3 +++ 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index 1f594b626d7a7734e8ec58766737a118c26bad94..5532450c9e9935399efbe9c5c6257293b6dcfc9e 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -537,6 +537,7 @@ static bool vm_get_shm_region(struct virtio_device *vdev, struct virtio_shm_region *region, u8 id) { struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); + u8 page_shift = 0; u64 len, addr; /* Select the region we're interested in */ @@ -560,7 +561,24 @@ static bool vm_get_shm_region(struct virtio_device *vdev, region->addr = addr; - region->page_size = 4096; + /* If supported by the device transport, read the region page size. + * The page_shift variable is initialized to zero above, so if this + * feature isn't supported it will result in a page_size of 4096, a + * default safe value. + */ + if (__virtio_test_bit(vdev, VIRTIO_F_SHM_PAGE_SIZE)) { + page_shift = (u8) readl(vm_dev->base + VIRTIO_MMIO_SHM_PAGE_SHIFT); + /* The value derived from page_shift must fit into a 32-bit + * unsigned integer. + */ + if ((page_shift + 12) >= 32) { + dev_err(&vdev->dev, "%s: device returned an invalid page shift: %d\n", + __func__, page_shift); + return false; + } + } + + region->page_size = 1U << (page_shift + 12); return true; } diff --git a/include/uapi/linux/virtio_mmio.h b/include/uapi/linux/virtio_mmio.h index 0650f91bea6c70f935764070d825d181a2379afb..43348be30eff90ee228b6490b9d3c35ba4c50aa5 100644 --- a/include/uapi/linux/virtio_mmio.h +++ b/include/uapi/linux/virtio_mmio.h @@ -133,6 +133,9 @@ #define VIRTIO_MMIO_SHM_BASE_LOW 0x0b8 #define VIRTIO_MMIO_SHM_BASE_HIGH 0x0bc +/* Shared memory region page shift */ +#define VIRTIO_MMIO_SHM_PAGE_SHIFT 0x0c4 + /* Configuration atomicity value */ #define VIRTIO_MMIO_CONFIG_GENERATION 0x0fc