linux-kernel - [PATCH 2/2] drm/vmwgfx: Refuse DMA operation when SEV encryption is active

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <20200311170839.3617-2-thomas_os@shipmail.org>
Date:   Wed, 11 Mar 2020 18:08:39 +0100
From:   Thomas Hellström (VMware) 
        <thomas_os@...pmail.org>
To:     dri-devel@...ts.freedesktop.org
Cc:     linux-kernel@...r.kernel.org, linux-graphics-maintainer@...are.com,
        Thomas Hellstrom <thellstrom@...are.com>,
        Brian Paul <brianp@...are.com>
Subject: [PATCH 2/2] drm/vmwgfx: Refuse DMA operation when SEV encryption is active

From: Thomas Hellstrom <thellstrom@...are.com>

TTM doesn't yet fully support mapping of DMA memory when SEV is active,
so in that case, refuse DMA operation. For guest-backed object operation
this means 3D acceleration will be disabled. For host-backed, VRAM will be
used for data transfer between the guest and the device.

Signed-off-by: Thomas Hellstrom <thellstrom@...are.com>
Reviewed-by: Brian Paul <brianp@...are.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index f2ec3155468d..4f58364421ce 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -29,6 +29,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/module.h>
 #include <linux/pci.h>
+#include <linux/mem_encrypt.h>
 
 #include <drm/drm_drv.h>
 #include <drm/drm_ioctl.h>
@@ -575,6 +576,10 @@ static int vmw_dma_select_mode(struct vmw_private *dev_priv)
 		[vmw_dma_map_populate] = "Caching DMA mappings.",
 		[vmw_dma_map_bind] = "Giving up DMA mappings early."};
 
+	/* TTM currently doesn't fully support SEV encryption. */
+	if (mem_encrypt_active())
+		return -EINVAL;
+
 	if (vmw_force_coherent)
 		dev_priv->map_mode = vmw_dma_alloc_coherent;
 	else if (vmw_restrict_iommu)
-- 
2.21.1