Mirrored_Repos/LookingGlass
1
0
Fork 0
mirror of https://github.com/gnif/LookingGlass.git synced 2024-11-25 06:47:19 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

[common] ivshmem: do not create dmabuf for simple mmap

Browse Source 
It used to be the case that you need to create dmabuf for kvmfr devices
to be able to mmap them. But after #457, this is no longer needed.

Directly mmaping the kvmfr device has the advantage of avoiding the
creation of a dmabuf, which has cost (e.g. the list of pages, the
scatterlist, etc.).
This commit is contained in:
Quantum 2021-02-07 16:00:07 -05:00 committed by Geoffrey McRae
parent 328f9078ee
commit 62b27760ea
1 changed files with 11 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
common/src/platform/linux/ivshmem.c
View File

@ -38,8 +38,8 @@ Place, Suite 330, Boston, MA 02111-1307 USA
struct IVSHMEMInfo
{
int devFd;
int dmaFd;
int size;
bool hasDMA;
};
static bool ivshmemDeviceValidator(struct Option * opt, const char ** error)
@ -119,8 +119,7 @@ bool ivshmemOpenDev(struct IVSHMEM * dev, const char * shmDevice)
unsigned int devSize;
int devFd = -1;
int dmaFd = -1;
int mapFd = -1;
bool hasDMA;
dev->opaque = NULL;
@ -138,22 +137,7 @@ bool ivshmemOpenDev(struct IVSHMEM * dev, const char * shmDevice)
// get the device size
devSize = ioctl(devFd, KVMFR_DMABUF_GETSIZE, 0);
const struct kvmfr_dmabuf_create create =
{
.flags = KVMFR_DMABUF_FLAG_CLOEXEC,
.offset = 0x0,
.size = devSize
};
dmaFd = ioctl(devFd, KVMFR_DMABUF_CREATE, &create);
if (dmaFd < 0)
{
DEBUG_ERROR("Failed to create the dma buffer");
close(devFd);
return false;
}
mapFd = dmaFd;
hasDMA = true;
}
else
{
@ -174,10 +158,10 @@ bool ivshmemOpenDev(struct IVSHMEM * dev, const char * shmDevice)
return false;
}
mapFd = devFd;
hasDMA = false;
}
void * map = mmap(0, devSize, PROT_READ | PROT_WRITE, MAP_SHARED, mapFd, 0);
void * map = mmap(0, devSize, PROT_READ | PROT_WRITE, MAP_SHARED, devFd, 0);
if (map == MAP_FAILED)
{
DEBUG_ERROR("Failed to map the shared memory device: %s", shmDevice);
@ -189,7 +173,7 @@ bool ivshmemOpenDev(struct IVSHMEM * dev, const char * shmDevice)
(struct IVSHMEMInfo *)malloc(sizeof(struct IVSHMEMInfo));
info->size = devSize;
info->devFd = devFd;
info->dmaFd = dmaFd;
info->hasDMA = hasDMA;
dev->opaque = info;
dev->size = devSize;
@ -208,10 +192,6 @@ void ivshmemClose(struct IVSHMEM * dev)
(struct IVSHMEMInfo *)dev->opaque;
munmap(dev->mem, info->size);
if (info->dmaFd >= 0)
close(info->dmaFd);
close(info->devFd);
free(info);
@ -232,7 +212,7 @@ bool ivshmemHasDMA(struct IVSHMEM * dev)
struct IVSHMEMInfo * info =
(struct IVSHMEMInfo *)dev->opaque;
return info->dmaFd >= 0;
return info->hasDMA;
}
int ivshmemGetDMABuf(struct IVSHMEM * dev, uint64_t offset, uint64_t size)