From: Andy Lutomirski <luto@kernel.org> To: "Michael S. Tsirkin" <mst@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>, David Woodhouse <dwmw2@infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "David S. Miller" <davem@davemloft.net>, sparclinux@vger.kernel.org, Joerg Roedel <jroedel@suse.de>, Christian Borntraeger <borntraeger@de.ibm.com>, Cornelia Huck <cornelia.huck@de.ibm.com>, Sebastian Ott <sebott@linux.vnet.ibm.com>, Paolo Bonzini <pbonzini@redhat.com>, Christoph Hellwig <hch@lst.de>, KVM <kvm@vger.kernel.org>, Martin Schwidefsky <schwidefsky@de.ibm.com>, linux-s390 <linux-s390@vger.kernel.org>, Linux Virtualization <virtualization@lists.linux-foundation.org>, David Vrabel <david.vrabel@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, xen-devel@lists.xenproject.org, Andy Lutomirski <luto@kernel.org> Subject: [PATCH v5 09/10] vring: Use the DMA API on Xen Date: Thu, 28 Jan 2016 18:31:22 -0800 [thread overview] Message-ID: <64e979cc139c5e6a9bbfae9f1bc5e6693d91bea9.1454034075.git.luto@kernel.org> (raw) In-Reply-To: <cover.1454034075.git.luto@kernel.org> In-Reply-To: <cover.1454034075.git.luto@kernel.org> Signed-off-by: Andy Lutomirski <luto@kernel.org> --- drivers/virtio/virtio_ring.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index c169c6444637..305c05cc249a 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -47,6 +47,18 @@ static bool vring_use_dma_api(void) { +#if defined(CONFIG_X86) && defined(CONFIG_XEN) + /* + * In theory, it's possible to have a buggy QEMU-supposed + * emulated Q35 IOMMU and Xen enabled at the same time. On + * such a configuration, virtio has never worked and will + * not work without an even larger kludge. Instead, enable + * the DMA API if we're a Xen guest, which at least allows + * all of the sensible Xen configurations to work correctly. + */ + return static_cpu_has(X86_FEATURE_XENPV); +#endif + return false; } -- 2.5.0
WARNING: multiple messages have this Message-ID (diff)
From: Andy Lutomirski <luto@kernel.org> To: "Michael S. Tsirkin" <mst@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>, David Woodhouse <dwmw2@infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "David S. Miller" <davem@davemloft.net>, sparclinux@vger.kernel.org, Joerg Roedel <jroedel@suse.de>, Christian Borntraeger <borntraeger@de.ibm.com>, Cornelia Huck <cornelia.huck@de.ibm.com>, Sebastian Ott <sebott@linux.vnet.ibm.com>, Paolo Bonzini <pbonzini@redhat.com>, Christoph Hellwig <hch@lst.de>, KVM <kvm@vger.kernel.org>, Martin Schwidefsky <schwidefsky@de.ibm.com>, linux-s390 <linux-s390@vger.kernel.org>, Linux Virtualization <virtualization@lists.linux-foundation.org>, David Vrabel <david.vrabel@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, xen-devel@lists.xenproject.org, Andy Lutomirski <luto@kernel.org> Subject: [PATCH v5 09/10] vring: Use the DMA API on Xen Date: Fri, 29 Jan 2016 02:31:22 +0000 [thread overview] Message-ID: <64e979cc139c5e6a9bbfae9f1bc5e6693d91bea9.1454034075.git.luto@kernel.org> (raw) In-Reply-To: <cover.1454034075.git.luto@kernel.org> Signed-off-by: Andy Lutomirski <luto@kernel.org> --- drivers/virtio/virtio_ring.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index c169c6444637..305c05cc249a 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -47,6 +47,18 @@ static bool vring_use_dma_api(void) { +#if defined(CONFIG_X86) && defined(CONFIG_XEN) + /* + * In theory, it's possible to have a buggy QEMU-supposed + * emulated Q35 IOMMU and Xen enabled at the same time. On + * such a configuration, virtio has never worked and will + * not work without an even larger kludge. Instead, enable + * the DMA API if we're a Xen guest, which at least allows + * all of the sensible Xen configurations to work correctly. + */ + return static_cpu_has(X86_FEATURE_XENPV); +#endif + return false; } -- 2.5.0
next prev parent reply other threads:[~2016-01-29 2:32 UTC|newest] Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-01-29 2:31 [PATCH v5 00/10] virtio DMA API, yet again Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` [PATCH v5 01/10] dma: Provide simple noop dma ops Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` [PATCH v5 02/10] alpha/dma: use common " Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` [PATCH v5 03/10] s390/dma: Allow per device " Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` [PATCH v5 04/10] vring: Introduce vring_use_dma_api() Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-02-01 11:22 ` David Woodhouse 2016-02-01 11:22 ` David Woodhouse 2016-02-01 11:22 ` David Woodhouse 2016-02-01 11:22 ` David Woodhouse 2016-02-01 13:23 ` Michael S. Tsirkin 2016-02-01 13:23 ` Michael S. Tsirkin 2016-02-01 13:23 ` Michael S. Tsirkin 2016-02-01 15:39 ` Andy Lutomirski 2016-02-01 15:39 ` Andy Lutomirski 2016-02-01 15:39 ` Andy Lutomirski 2016-02-01 16:11 ` David Woodhouse 2016-02-01 16:11 ` David Woodhouse 2016-02-01 16:11 ` David Woodhouse 2016-02-01 15:39 ` Andy Lutomirski 2016-02-01 13:23 ` Michael S. Tsirkin 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` [PATCH v5 05/10] virtio_ring: Support DMA APIs Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` [PATCH v5 06/10] virtio: Add improved queue allocation API Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` [PATCH v5 07/10] virtio_mmio: Use the DMA API if enabled Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` [PATCH v5 08/10] virtio_pci: " Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski [this message] 2016-01-29 2:31 ` [PATCH v5 09/10] vring: Use the DMA API on Xen Andy Lutomirski 2016-01-29 10:34 ` [Xen-devel] " David Vrabel 2016-01-29 10:34 ` David Vrabel 2016-01-29 10:34 ` David Vrabel 2016-01-31 20:09 ` Michael S. Tsirkin 2016-01-31 20:09 ` Michael S. Tsirkin 2016-01-31 20:09 ` Michael S. Tsirkin 2016-01-31 20:13 ` Andy Lutomirski 2016-01-31 20:13 ` Andy Lutomirski 2016-01-31 20:13 ` Andy Lutomirski 2016-01-31 20:18 ` Michael S. Tsirkin 2016-01-31 20:18 ` [Xen-devel] " Michael S. Tsirkin 2016-01-31 20:18 ` Michael S. Tsirkin 2016-01-31 20:18 ` Michael S. Tsirkin 2016-01-31 20:27 ` Andy Lutomirski 2016-01-31 20:27 ` Andy Lutomirski 2016-01-31 20:27 ` Andy Lutomirski 2016-01-31 20:27 ` Andy Lutomirski 2016-01-31 20:13 ` Andy Lutomirski 2016-02-01 21:24 ` [Xen-devel] " Wei Liu 2016-02-01 21:24 ` Wei Liu 2016-02-01 21:24 ` Wei Liu 2016-02-01 21:24 ` Wei Liu 2016-01-31 20:09 ` Michael S. Tsirkin 2016-01-29 10:34 ` David Vrabel 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` [PATCH v5 10/10] vring: Add a module parameter to force-enable the DMA API Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 2:31 ` Andy Lutomirski 2016-01-29 11:01 ` [PATCH v5 00/10] virtio DMA API, yet again David Woodhouse 2016-01-29 11:01 ` David Woodhouse 2016-01-29 11:01 ` David Woodhouse 2016-01-31 19:06 ` Christoph Hellwig 2016-01-31 19:06 ` Christoph Hellwig 2016-01-31 19:06 ` Christoph Hellwig 2016-01-31 19:06 ` Christoph Hellwig 2016-01-31 20:12 ` Michael S. Tsirkin 2016-01-31 20:12 ` Michael S. Tsirkin 2016-01-31 20:12 ` Michael S. Tsirkin 2016-01-31 20:12 ` Michael S. Tsirkin 2016-01-31 20:16 ` Andy Lutomirski 2016-01-31 20:16 ` Andy Lutomirski 2016-01-31 20:16 ` Andy Lutomirski 2016-01-31 20:16 ` Andy Lutomirski 2016-02-01 11:00 ` [Xen-devel] " Wei Liu 2016-02-01 11:00 ` Wei Liu 2016-02-01 11:00 ` Wei Liu 2016-02-01 18:04 ` Andy Lutomirski 2016-02-01 18:04 ` [Xen-devel] " Andy Lutomirski 2016-02-01 18:04 ` Andy Lutomirski 2016-02-01 18:04 ` Andy Lutomirski 2016-02-01 21:22 ` Wei Liu 2016-02-01 21:22 ` Wei Liu 2016-02-01 21:22 ` Wei Liu 2016-02-01 21:22 ` Wei Liu 2016-02-01 11:00 ` Wei Liu
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