[PATCH] drm/vmwgfx: Use dma-coherent memory for high-bandwidth port messaging
Thomas Hellström (VMware)
thomas_os at shipmail.org
Wed Nov 13 09:51:42 UTC 2019
From: Thomas Hellstrom <thellstrom at vmware.com>
With AMD-SEV high-bandwidth port messaging runs into trouble since the
message content is encrypted using the vm-specific key, and the
hypervisor is unable to read it.
So use unencrypted dma-coherent bounce buffers for temporary message
storage space. Allocating that memory is expensive so a future
optimization might include a static unencrypted memory area for messages.
Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
Reviewed-by: Brian Paul <brianp at vmware.com>
---
drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 4 +--
drivers/gpu/drm/vmwgfx/vmwgfx_drv.h | 4 +--
drivers/gpu/drm/vmwgfx/vmwgfx_msg.c | 45 +++++++++++++++++------------
3 files changed, 31 insertions(+), 22 deletions(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
index 81a95651643f..fc0283659c41 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c
@@ -908,13 +908,13 @@ static int vmw_driver_load(struct drm_device *dev, unsigned long chipset)
snprintf(host_log, sizeof(host_log), "vmwgfx: %s-%s",
VMWGFX_REPO, VMWGFX_GIT_VERSION);
- vmw_host_log(host_log);
+ vmw_host_log(dev->dev, host_log);
memset(host_log, 0, sizeof(host_log));
snprintf(host_log, sizeof(host_log), "vmwgfx: Module Version: %d.%d.%d",
VMWGFX_DRIVER_MAJOR, VMWGFX_DRIVER_MINOR,
VMWGFX_DRIVER_PATCHLEVEL);
- vmw_host_log(host_log);
+ vmw_host_log(dev->dev, host_log);
if (dev_priv->enable_fb) {
vmw_fifo_resource_inc(dev_priv);
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index b18842f73081..a77bf72cb9ac 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -1389,9 +1389,9 @@ int vmw_bo_cpu_blit(struct ttm_buffer_object *dst,
struct vmw_diff_cpy *diff);
/* Host messaging -vmwgfx_msg.c: */
-int vmw_host_get_guestinfo(const char *guest_info_param,
+int vmw_host_get_guestinfo(struct device *dev, const char *guest_info_param,
char *buffer, size_t *length);
-int vmw_host_log(const char *log);
+int vmw_host_log(struct device *dev, const char *log);
/* VMW logging */
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c b/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
index b6c5e4c2ac3c..f439b7afa3a5 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_msg.c
@@ -304,8 +304,8 @@ STACK_FRAME_NON_STANDARD(vmw_send_msg);
* @msg: [OUT] message received from the host
* @msg_len: message length
*/
-static int vmw_recv_msg(struct rpc_channel *channel, void **msg,
- size_t *msg_len)
+static int vmw_recv_msg(struct device *dev, struct rpc_channel *channel,
+ void **msg, size_t *msg_len, dma_addr_t *dma_handle)
{
unsigned long eax, ebx, ecx, edx, si, di;
char *reply;
@@ -339,7 +339,8 @@ static int vmw_recv_msg(struct rpc_channel *channel, void **msg,
return 0;
reply_len = ebx;
- reply = kzalloc(reply_len + 1, GFP_KERNEL);
+ reply = dma_alloc_coherent(dev, reply_len + 1, dma_handle,
+ GFP_KERNEL);
if (!reply) {
DRM_ERROR("Cannot allocate memory for host message reply.\n");
return -ENOMEM;
@@ -350,7 +351,7 @@ static int vmw_recv_msg(struct rpc_channel *channel, void **msg,
ebx = vmw_port_hb_in(channel, reply, reply_len,
!!(HIGH_WORD(ecx) & MESSAGE_STATUS_HB));
if ((HIGH_WORD(ebx) & MESSAGE_STATUS_SUCCESS) == 0) {
- kfree(reply);
+ dma_free_coherent(dev, reply_len + 1, reply, *dma_handle);
reply = NULL;
if ((HIGH_WORD(ebx) & MESSAGE_STATUS_CPT) != 0) {
/* A checkpoint occurred. Retry. */
@@ -374,7 +375,7 @@ static int vmw_recv_msg(struct rpc_channel *channel, void **msg,
eax, ebx, ecx, edx, si, di);
if ((HIGH_WORD(ecx) & MESSAGE_STATUS_SUCCESS) == 0) {
- kfree(reply);
+ dma_free_coherent(dev, reply_len + 1, reply, *dma_handle);
reply = NULL;
if ((HIGH_WORD(ecx) & MESSAGE_STATUS_CPT) != 0) {
/* A checkpoint occurred. Retry. */
@@ -404,18 +405,21 @@ STACK_FRAME_NON_STANDARD(vmw_recv_msg);
* Gets the value of a GuestInfo.* parameter. The value returned will be in
* a string, and it is up to the caller to post-process.
*
+ * @dev: Pointer to struct device used for coherent memory allocation
* @guest_info_param: Parameter to get, e.g. GuestInfo.svga.gl3
* @buffer: if NULL, *reply_len will contain reply size.
* @length: size of the reply_buf. Set to size of reply upon return
*
* Returns: 0 on success
*/
-int vmw_host_get_guestinfo(const char *guest_info_param,
+int vmw_host_get_guestinfo(struct device *dev, const char *guest_info_param,
char *buffer, size_t *length)
{
struct rpc_channel channel;
char *msg, *reply = NULL;
size_t reply_len = 0;
+ dma_addr_t req_handle, reply_handle;
+ int req_len = strlen("info-get ") + strlen(guest_info_param) + 1;
if (!vmw_msg_enabled)
return -ENODEV;
@@ -423,18 +427,20 @@ int vmw_host_get_guestinfo(const char *guest_info_param,
if (!guest_info_param || !length)
return -EINVAL;
- msg = kasprintf(GFP_KERNEL, "info-get %s", guest_info_param);
+ msg = dma_alloc_coherent(dev, req_len, &req_handle, GFP_KERNEL);
if (!msg) {
DRM_ERROR("Cannot allocate memory to get guest info \"%s\".",
guest_info_param);
return -ENOMEM;
}
+ snprintf(msg, req_len, "info-get %s", guest_info_param);
if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM))
goto out_open;
if (vmw_send_msg(&channel, msg) ||
- vmw_recv_msg(&channel, (void *) &reply, &reply_len))
+ vmw_recv_msg(dev, &channel, (void *) &reply, &reply_len,
+ &reply_handle))
goto out_msg;
vmw_close_channel(&channel);
@@ -451,19 +457,19 @@ int vmw_host_get_guestinfo(const char *guest_info_param,
*length = reply_len;
- kfree(reply);
- kfree(msg);
+ dma_free_coherent(dev, reply_len + 1, reply, reply_handle);
+ dma_free_coherent(dev, req_len, msg, req_handle);
return 0;
out_msg:
vmw_close_channel(&channel);
- kfree(reply);
+ dma_free_coherent(dev, reply_len + 1, reply, reply_handle);
out_open:
*length = 0;
- kfree(msg);
- DRM_ERROR("Failed to get guest info \"%s\".", guest_info_param);
+ DRM_ERROR("Failed to get guest info \"%s\".", guest_info_param);
+ dma_free_coherent(dev, req_len, msg, req_handle);
return -EINVAL;
}
@@ -472,16 +478,18 @@ int vmw_host_get_guestinfo(const char *guest_info_param,
/**
* vmw_host_log: Sends a log message to the host
*
+ * @dev: Pointer to struct device used for coherent memory allocation
* @log: NULL terminated string
*
* Returns: 0 on success
*/
-int vmw_host_log(const char *log)
+int vmw_host_log(struct device *dev, const char *log)
{
struct rpc_channel channel;
char *msg;
int ret = 0;
-
+ dma_addr_t log_handle;
+ int log_len = strlen("log ") + strlen(log) + 1;
if (!vmw_msg_enabled)
return -ENODEV;
@@ -489,11 +497,12 @@ int vmw_host_log(const char *log)
if (!log)
return ret;
- msg = kasprintf(GFP_KERNEL, "log %s", log);
+ msg = dma_alloc_coherent(dev, log_len, &log_handle, GFP_KERNEL);
if (!msg) {
DRM_ERROR("Cannot allocate memory for host log message.\n");
return -ENOMEM;
}
+ snprintf(msg, log_len, "log %s", log);
if (vmw_open_channel(&channel, RPCI_PROTOCOL_NUM))
goto out_open;
@@ -502,14 +511,14 @@ int vmw_host_log(const char *log)
goto out_msg;
vmw_close_channel(&channel);
- kfree(msg);
+ dma_free_coherent(dev, log_len, msg, log_handle);
return 0;
out_msg:
vmw_close_channel(&channel);
out_open:
- kfree(msg);
+ dma_free_coherent(dev, log_len, msg, log_handle);
DRM_ERROR("Failed to send host log message.\n");
return -EINVAL;
--
2.21.0
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