Re: [PATCH v3] virtio_pmem: fix sparse warning
On Fri, Jul 12, 2019 at 7:11 AM Michael S. Tsirkin wrote: > > On Fri, Jul 12, 2019 at 10:46:10AM +0530, Pankaj Gupta wrote: > > This patch fixes below sparse warning related to __virtio > > type in virtio pmem driver. This is reported by Intel test > > bot on linux-next tree. > > > > nd_virtio.c:56:28: warning: incorrect type in assignment > > (different base types) > > nd_virtio.c:56:28:expected unsigned int [unsigned] [usertype] type > > nd_virtio.c:56:28:got restricted __virtio32 > > nd_virtio.c:93:59: warning: incorrect type in argument 2 > > (different base types) > > nd_virtio.c:93:59:expected restricted __virtio32 [usertype] val > > nd_virtio.c:93:59:got unsigned int [unsigned] [usertype] ret > > > > Reported-by: kbuild test robot > > Signed-off-by: Pankaj Gupta > > Acked-by: Michael S. Tsirkin > > Pls merge - I assume nvdimm tree? Yes, I'll push this with the rest to Linus tomorrow morning. ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
[PATCH v3 2/3] drm: plumb attaching dev thru to prime_pin/unpin
From: Rob Clark
Needed in the following patch for cache operations.
Signed-off-by: Rob Clark
---
v3: rebased on drm-tip
drivers/gpu/drm/drm_gem.c | 8
drivers/gpu/drm/drm_internal.h | 4 ++--
drivers/gpu/drm/drm_prime.c | 4 ++--
drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 4 ++--
drivers/gpu/drm/msm/msm_drv.h | 4 ++--
drivers/gpu/drm/msm/msm_gem_prime.c | 4 ++--
drivers/gpu/drm/nouveau/nouveau_gem.h | 4 ++--
drivers/gpu/drm/nouveau/nouveau_prime.c | 4 ++--
drivers/gpu/drm/qxl/qxl_prime.c | 4 ++--
drivers/gpu/drm/radeon/radeon_prime.c | 4 ++--
drivers/gpu/drm/vgem/vgem_drv.c | 4 ++--
include/drm/drm_drv.h | 5 ++---
12 files changed, 26 insertions(+), 27 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 84689ccae885..af2549c45027 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1215,22 +1215,22 @@ void drm_gem_print_info(struct drm_printer *p, unsigned
int indent,
obj->dev->driver->gem_print_info(p, indent, obj);
}
-int drm_gem_pin(struct drm_gem_object *obj)
+int drm_gem_pin(struct drm_gem_object *obj, struct device *dev)
{
if (obj->funcs && obj->funcs->pin)
return obj->funcs->pin(obj);
else if (obj->dev->driver->gem_prime_pin)
- return obj->dev->driver->gem_prime_pin(obj);
+ return obj->dev->driver->gem_prime_pin(obj, dev);
else
return 0;
}
-void drm_gem_unpin(struct drm_gem_object *obj)
+void drm_gem_unpin(struct drm_gem_object *obj, struct device *dev)
{
if (obj->funcs && obj->funcs->unpin)
obj->funcs->unpin(obj);
else if (obj->dev->driver->gem_prime_unpin)
- obj->dev->driver->gem_prime_unpin(obj);
+ obj->dev->driver->gem_prime_unpin(obj, dev);
}
void *drm_gem_vmap(struct drm_gem_object *obj)
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index 51a2055c8f18..e64090373e3a 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -133,8 +133,8 @@ void drm_gem_release(struct drm_device *dev, struct
drm_file *file_private);
void drm_gem_print_info(struct drm_printer *p, unsigned int indent,
const struct drm_gem_object *obj);
-int drm_gem_pin(struct drm_gem_object *obj);
-void drm_gem_unpin(struct drm_gem_object *obj);
+int drm_gem_pin(struct drm_gem_object *obj, struct device *dev);
+void drm_gem_unpin(struct drm_gem_object *obj, struct device *dev);
void *drm_gem_vmap(struct drm_gem_object *obj);
void drm_gem_vunmap(struct drm_gem_object *obj, void *vaddr);
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 189d980402ad..126860432ff9 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -575,7 +575,7 @@ int drm_gem_map_attach(struct dma_buf *dma_buf,
{
struct drm_gem_object *obj = dma_buf->priv;
- return drm_gem_pin(obj);
+ return drm_gem_pin(obj, attach->dev);
}
EXPORT_SYMBOL(drm_gem_map_attach);
@@ -593,7 +593,7 @@ void drm_gem_map_detach(struct dma_buf *dma_buf,
{
struct drm_gem_object *obj = dma_buf->priv;
- drm_gem_unpin(obj);
+ drm_gem_unpin(obj, attach->dev);
}
EXPORT_SYMBOL(drm_gem_map_detach);
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
index a05292e8ed6f..67e69a5f00f2 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
@@ -43,7 +43,7 @@ int etnaviv_gem_prime_mmap(struct drm_gem_object *obj,
return etnaviv_obj->ops->mmap(etnaviv_obj, vma);
}
-int etnaviv_gem_prime_pin(struct drm_gem_object *obj)
+int etnaviv_gem_prime_pin(struct drm_gem_object *obj, struct device *dev)
{
if (!obj->import_attach) {
struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
@@ -55,7 +55,7 @@ int etnaviv_gem_prime_pin(struct drm_gem_object *obj)
return 0;
}
-void etnaviv_gem_prime_unpin(struct drm_gem_object *obj)
+void etnaviv_gem_prime_unpin(struct drm_gem_object *obj, struct device *dev)
{
if (!obj->import_attach) {
struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index ee7b512dc158..0eea68618b68 100644
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -288,8 +288,8 @@ void msm_gem_prime_vunmap(struct drm_gem_object *obj, void
*vaddr);
int msm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
struct drm_gem_object *msm_gem_prime_import_sg_table(struct drm_device *dev,
struct dma_buf_attachment *attach, struct sg_table *sg);
-int msm_gem_prime_pin(struct drm_gem_object *obj);
-void
Re: [PATCH v2 2/3] drm: plumb attaching dev thru to prime_pin/unpin
Quoting Rob Clark (2019-07-16 18:43:22) > From: Rob Clark > > Needed in the following patch for cache operations. What's the base for this patch? (I'm missing the ancestor for drm_gem.c) -Chris ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
[PATCH v2 2/3] drm: plumb attaching dev thru to prime_pin/unpin
From: Rob Clark
Needed in the following patch for cache operations.
Signed-off-by: Rob Clark
---
drivers/gpu/drm/drm_gem.c | 10 ++
drivers/gpu/drm/drm_gem_vram_helper.c | 6 --
drivers/gpu/drm/drm_prime.c | 4 ++--
drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c | 4 ++--
drivers/gpu/drm/msm/msm_drv.h | 4 ++--
drivers/gpu/drm/msm/msm_gem_prime.c | 4 ++--
drivers/gpu/drm/nouveau/nouveau_gem.h | 4 ++--
drivers/gpu/drm/nouveau/nouveau_prime.c | 4 ++--
drivers/gpu/drm/qxl/qxl_prime.c | 4 ++--
drivers/gpu/drm/radeon/radeon_prime.c | 4 ++--
drivers/gpu/drm/vboxvideo/vbox_prime.c | 4 ++--
drivers/gpu/drm/vgem/vgem_drv.c | 4 ++--
include/drm/drm_drv.h | 4 ++--
include/drm/drm_gem.h | 4 ++--
include/drm/drm_gem_vram_helper.h | 4 ++--
15 files changed, 36 insertions(+), 32 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 7d6242cc69f2..0a2645769624 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1219,18 +1219,19 @@ void drm_gem_print_info(struct drm_printer *p, unsigned
int indent,
/**
* drm_gem_pin - Pin backing buffer in memory
* @obj: GEM object
+ * @dev: the device the buffer is being pinned for
*
* Make sure the backing buffer is pinned in memory.
*
* Returns:
* 0 on success or a negative error code on failure.
*/
-int drm_gem_pin(struct drm_gem_object *obj)
+int drm_gem_pin(struct drm_gem_object *obj, struct device *dev)
{
if (obj->funcs && obj->funcs->pin)
return obj->funcs->pin(obj);
else if (obj->dev->driver->gem_prime_pin)
- return obj->dev->driver->gem_prime_pin(obj);
+ return obj->dev->driver->gem_prime_pin(obj, dev);
else
return 0;
}
@@ -1239,15 +1240,16 @@ EXPORT_SYMBOL(drm_gem_pin);
/**
* drm_gem_unpin - Unpin backing buffer from memory
* @obj: GEM object
+ * @dev: the device the buffer is being pinned for
*
* Relax the requirement that the backing buffer is pinned in memory.
*/
-void drm_gem_unpin(struct drm_gem_object *obj)
+void drm_gem_unpin(struct drm_gem_object *obj, struct device *dev)
{
if (obj->funcs && obj->funcs->unpin)
obj->funcs->unpin(obj);
else if (obj->dev->driver->gem_prime_unpin)
- obj->dev->driver->gem_prime_unpin(obj);
+ obj->dev->driver->gem_prime_unpin(obj, dev);
}
EXPORT_SYMBOL(drm_gem_unpin);
diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c
b/drivers/gpu/drm/drm_gem_vram_helper.c
index 4de782ca26b2..62fafec93948 100644
--- a/drivers/gpu/drm/drm_gem_vram_helper.c
+++ b/drivers/gpu/drm/drm_gem_vram_helper.c
@@ -548,7 +548,8 @@ EXPORT_SYMBOL(drm_gem_vram_driver_dumb_mmap_offset);
* 0 on success, or
* a negative errno code otherwise.
*/
-int drm_gem_vram_driver_gem_prime_pin(struct drm_gem_object *gem)
+int drm_gem_vram_driver_gem_prime_pin(struct drm_gem_object *gem,
+ struct device *dev)
{
struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
@@ -569,7 +570,8 @@ EXPORT_SYMBOL(drm_gem_vram_driver_gem_prime_pin);
Implements drm_driver.gem_prime_unpin
* @gem: The GEM object to unpin
*/
-void drm_gem_vram_driver_gem_prime_unpin(struct drm_gem_object *gem)
+void drm_gem_vram_driver_gem_prime_unpin(struct drm_gem_object *gem,
+struct device *dev)
{
struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index d0c01318076b..505893cfac8e 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -196,7 +196,7 @@ int drm_gem_map_attach(struct dma_buf *dma_buf,
{
struct drm_gem_object *obj = dma_buf->priv;
- return drm_gem_pin(obj);
+ return drm_gem_pin(obj, attach->dev);
}
EXPORT_SYMBOL(drm_gem_map_attach);
@@ -213,7 +213,7 @@ void drm_gem_map_detach(struct dma_buf *dma_buf,
{
struct drm_gem_object *obj = dma_buf->priv;
- drm_gem_unpin(obj);
+ drm_gem_unpin(obj, attach->dev);
}
EXPORT_SYMBOL(drm_gem_map_detach);
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
index 00e8b6a817e3..44385d590aa7 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_prime.c
@@ -43,7 +43,7 @@ int etnaviv_gem_prime_mmap(struct drm_gem_object *obj,
return etnaviv_obj->ops->mmap(etnaviv_obj, vma);
}
-int etnaviv_gem_prime_pin(struct drm_gem_object *obj)
+int etnaviv_gem_prime_pin(struct drm_gem_object *obj, struct device *dev)
{
if (!obj->import_attach) {
struct etnaviv_gem_object *etnaviv_obj = to_etnaviv_bo(obj);
@@ -55,7 +55,7 @@ int etnaviv_gem_prime_pin(struct
[PULL] virtio, vhost: fixes, features, performance
The following changes since commit c1ea02f15ab5efb3e93fc3144d895410bf79fcf2:
vhost: scsi: add weight support (2019-05-27 11:08:23 -0400)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git tags/for_linus
for you to fetch changes up to 5e663f0410fa2f355042209154029842ba1abd43:
virtio-mmio: add error check for platform_get_irq (2019-07-11 16:22:29 -0400)
virtio, vhost: fixes, features, performance
new iommu device
vhost guest memory access using vmap (just meta-data for now)
minor fixes
Signed-off-by: Michael S. Tsirkin
Note: due to code driver changes the driver-core tree, the following
patch is needed when merging tree with commit 92ce7e83b4e5
("driver_find_device: Unify the match function with
class_find_device()") in the driver-core tree:
From: Nathan Chancellor
Subject: [PATCH] iommu/virtio: Constify data parameter in viommu_match_node
After commit 92ce7e83b4e5 ("driver_find_device: Unify the match
function with class_find_device()") in the driver-core tree.
Signed-off-by: Nathan Chancellor
Signed-off-by: Michael S. Tsirkin
---
drivers/iommu/virtio-iommu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 4620dd221ffd..433f4d2ee956 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -839,7 +839,7 @@ static void viommu_put_resv_regions(struct device *dev,
struct list_head *head)
static struct iommu_ops viommu_ops;
static struct virtio_driver virtio_iommu_drv;
-static int viommu_match_node(struct device *dev, void *data)
+static int viommu_match_node(struct device *dev, const void *data)
{
return dev->parent->fwnode == data;
}
Gustavo A. R. Silva (1):
scsi: virtio_scsi: Use struct_size() helper
Ihor Matushchak (1):
virtio-mmio: add error check for platform_get_irq
Jason Wang (6):
vhost: generalize adding used elem
vhost: fine grain userspace memory accessors
vhost: rename vq_iotlb_prefetch() to vq_meta_prefetch()
vhost: introduce helpers to get the size of metadata area
vhost: factor out setting vring addr and num
vhost: access vq metadata through kernel virtual address
Jean-Philippe Brucker (7):
dt-bindings: virtio-mmio: Add IOMMU description
dt-bindings: virtio: Add virtio-pci-iommu node
of: Allow the iommu-map property to omit untranslated devices
PCI: OF: Initialize dev->fwnode appropriately
iommu: Add virtio-iommu driver
iommu/virtio: Add probe request
iommu/virtio: Add event queue
Michael S. Tsirkin (1):
vhost: fix clang build warning
Documentation/devicetree/bindings/virtio/iommu.txt | 66 ++
Documentation/devicetree/bindings/virtio/mmio.txt | 30 +
MAINTAINERS|7 +
drivers/iommu/Kconfig | 11 +
drivers/iommu/Makefile |1 +
drivers/iommu/virtio-iommu.c | 1158
drivers/of/base.c | 10 +-
drivers/pci/of.c |8 +
drivers/scsi/virtio_scsi.c |2 +-
drivers/vhost/net.c|4 +-
drivers/vhost/vhost.c | 850 +++---
drivers/vhost/vhost.h | 43 +-
drivers/virtio/virtio_mmio.c |7 +-
include/uapi/linux/virtio_ids.h|1 +
include/uapi/linux/virtio_iommu.h | 161 +++
15 files changed, 2228 insertions(+), 131 deletions(-)
create mode 100644 Documentation/devicetree/bindings/virtio/iommu.txt
create mode 100644 drivers/iommu/virtio-iommu.c
create mode 100644 include/uapi/linux/virtio_iommu.h
___
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Re: [RFC] virtio-net: share receive_*() and add_recvbuf_*() with virtio-vsock
On Tue, Jul 16, 2019 at 06:01:33AM -0400, Michael S. Tsirkin wrote: > On Tue, Jul 16, 2019 at 11:40:24AM +0200, Stefano Garzarella wrote: > > On Mon, Jul 15, 2019 at 01:50:28PM -0400, Michael S. Tsirkin wrote: > > > On Mon, Jul 15, 2019 at 09:44:16AM +0200, Stefano Garzarella wrote: > > > > On Fri, Jul 12, 2019 at 06:14:39PM +0800, Jason Wang wrote: > > > > [...] > > > > > > > > > > > > > > > > > I think it's just a branch, for ethernet, go for networking stack. > > > > > otherwise > > > > > go for vsock core? > > > > > > > > > > > > > Yes, that should work. > > > > > > > > So, I should refactor the functions that can be called also from the > > > > vsock > > > > core, in order to remove "struct net_device *dev" parameter. > > > > Maybe creating some wrappers for the network stack. > > > > > > > > Otherwise I should create a fake net_device for vsock_core. > > > > > > > > What do you suggest? > > > > > > Neither. > > > > > > I think what Jason was saying all along is this: > > > > > > virtio net doesn't actually lose packets, at least most > > > of the time. And it actually most of the time > > > passes all packets to host. So it's possible to use a virtio net > > > device (possibly with a feature flag that says "does not lose packets, > > > all packets go to host") and build vsock on top. > > > > Yes, I got it after the latest Jason's reply. > > > > > > > > and all of this is nice, but don't expect anything easy, > > > or any quick results. > > > > I expected this... :-( > > > > > > > > Also, in a sense it's a missed opportunity: we could cut out a lot > > > of fat and see just how fast can a protocol that is completely > > > new and separate from networking stack go. > > > > In this case, if we will try to do a PoC, what do you think is better? > > 1. new AF_VSOCK + network-stack + virtio-net modified > > Maybe it is allow us to reuse a lot of stuff already written, > > but we will go through the network stack > > > > 2. new AF_VSOCK + glue + virtio-net modified > > Intermediate approach, similar to Jason's proposal > > > > 3, new AF_VSOCK + new virtio-vsock > > Can be the thinnest, but we have to rewrite many things, with the > > risk > > of making the same mistakes as the current implementation. > > > > 1 or 3 imho. I wouldn't expect a lot from 2. I slightly favor 3 and > Jason 1. So take your pick :) > Yes, I agree :) Maybe "Jason 1" could be the short term (and an opportunity to study better the code and sources of overhead) and "new AF_VSOCK + new virtio-vsock" the long term goal with the multi-transport support in mind. Thank you so much for your guidance and useful advice, Stefano ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFC] virtio-net: share receive_*() and add_recvbuf_*() with virtio-vsock
On Tue, Jul 16, 2019 at 11:40:24AM +0200, Stefano Garzarella wrote: > On Mon, Jul 15, 2019 at 01:50:28PM -0400, Michael S. Tsirkin wrote: > > On Mon, Jul 15, 2019 at 09:44:16AM +0200, Stefano Garzarella wrote: > > > On Fri, Jul 12, 2019 at 06:14:39PM +0800, Jason Wang wrote: > > [...] > > > > > > > > > > > > > I think it's just a branch, for ethernet, go for networking stack. > > > > otherwise > > > > go for vsock core? > > > > > > > > > > Yes, that should work. > > > > > > So, I should refactor the functions that can be called also from the vsock > > > core, in order to remove "struct net_device *dev" parameter. > > > Maybe creating some wrappers for the network stack. > > > > > > Otherwise I should create a fake net_device for vsock_core. > > > > > > What do you suggest? > > > > Neither. > > > > I think what Jason was saying all along is this: > > > > virtio net doesn't actually lose packets, at least most > > of the time. And it actually most of the time > > passes all packets to host. So it's possible to use a virtio net > > device (possibly with a feature flag that says "does not lose packets, > > all packets go to host") and build vsock on top. > > Yes, I got it after the latest Jason's reply. > > > > > and all of this is nice, but don't expect anything easy, > > or any quick results. > > I expected this... :-( > > > > > Also, in a sense it's a missed opportunity: we could cut out a lot > > of fat and see just how fast can a protocol that is completely > > new and separate from networking stack go. > > In this case, if we will try to do a PoC, what do you think is better? > 1. new AF_VSOCK + network-stack + virtio-net modified > Maybe it is allow us to reuse a lot of stuff already written, > but we will go through the network stack > > 2. new AF_VSOCK + glue + virtio-net modified > Intermediate approach, similar to Jason's proposal > > 3, new AF_VSOCK + new virtio-vsock > Can be the thinnest, but we have to rewrite many things, with the risk > of making the same mistakes as the current implementation. > 1 or 3 imho. I wouldn't expect a lot from 2. I slightly favor 3 and Jason 1. So take your pick :) > > Instead vsock implementation carries so much baggage from both > > networking stack - such as softirq processing - and itself such as > > workqueues, global state and crude locking - to the point where > > it's actually slower than TCP. > > I agree, and I'm finding new issues while I'm trying to support nested > VMs, allowing multiple vsock transports (virtio-vsock and vhost-vsock in > the KVM case) at runtime. > > > > > [...] > > > > > > > > > I suggest to do this step by step: > > > > > > > > 1) use virtio-net but keep some protocol logic > > > > > > > > 2) separate protocol logic and merge it to exist Linux networking stack > > > > > > Make sense, thanks for the suggestions, I'll try to do these steps! > > > > > > Thanks, > > > Stefano > > > > > > An alternative is look at sources of overhead in vsock and get rid of > > them, or rewrite it from scratch focusing on performance. > > I started looking at virtio-vsock and vhost-vsock trying to do very > simple changes [1] to increase the performance. I should send a v4 of that > series as a very short term, then I'd like to have a deeper look to understand > if it is better to try to optimize or rewrite it from scratch. > > > Thanks, > Stefano > > [1] https://patchwork.kernel.org/cover/10970145/ ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [RFC] virtio-net: share receive_*() and add_recvbuf_*() with virtio-vsock
On Mon, Jul 15, 2019 at 01:50:28PM -0400, Michael S. Tsirkin wrote: > On Mon, Jul 15, 2019 at 09:44:16AM +0200, Stefano Garzarella wrote: > > On Fri, Jul 12, 2019 at 06:14:39PM +0800, Jason Wang wrote: [...] > > > > > > > > > I think it's just a branch, for ethernet, go for networking stack. > > > otherwise > > > go for vsock core? > > > > > > > Yes, that should work. > > > > So, I should refactor the functions that can be called also from the vsock > > core, in order to remove "struct net_device *dev" parameter. > > Maybe creating some wrappers for the network stack. > > > > Otherwise I should create a fake net_device for vsock_core. > > > > What do you suggest? > > Neither. > > I think what Jason was saying all along is this: > > virtio net doesn't actually lose packets, at least most > of the time. And it actually most of the time > passes all packets to host. So it's possible to use a virtio net > device (possibly with a feature flag that says "does not lose packets, > all packets go to host") and build vsock on top. Yes, I got it after the latest Jason's reply. > > and all of this is nice, but don't expect anything easy, > or any quick results. I expected this... :-( > > Also, in a sense it's a missed opportunity: we could cut out a lot > of fat and see just how fast can a protocol that is completely > new and separate from networking stack go. In this case, if we will try to do a PoC, what do you think is better? 1. new AF_VSOCK + network-stack + virtio-net modified Maybe it is allow us to reuse a lot of stuff already written, but we will go through the network stack 2. new AF_VSOCK + glue + virtio-net modified Intermediate approach, similar to Jason's proposal 3, new AF_VSOCK + new virtio-vsock Can be the thinnest, but we have to rewrite many things, with the risk of making the same mistakes as the current implementation. > Instead vsock implementation carries so much baggage from both > networking stack - such as softirq processing - and itself such as > workqueues, global state and crude locking - to the point where > it's actually slower than TCP. I agree, and I'm finding new issues while I'm trying to support nested VMs, allowing multiple vsock transports (virtio-vsock and vhost-vsock in the KVM case) at runtime. > [...] > > > > > > I suggest to do this step by step: > > > > > > 1) use virtio-net but keep some protocol logic > > > > > > 2) separate protocol logic and merge it to exist Linux networking stack > > > > Make sense, thanks for the suggestions, I'll try to do these steps! > > > > Thanks, > > Stefano > > > An alternative is look at sources of overhead in vsock and get rid of > them, or rewrite it from scratch focusing on performance. I started looking at virtio-vsock and vhost-vsock trying to do very simple changes [1] to increase the performance. I should send a v4 of that series as a very short term, then I'd like to have a deeper look to understand if it is better to try to optimize or rewrite it from scratch. Thanks, Stefano [1] https://patchwork.kernel.org/cover/10970145/ ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
Re: [Xen-devel] [PATCH 0/2] Remove 32-bit Xen PV guest support
On 15.07.2019 19:28, Andy Lutomirski wrote: > On Mon, Jul 15, 2019 at 9:34 AM Andi Kleen wrote: >> >> Juergen Gross writes: >> >>> The long term plan has been to replace Xen PV guests by PVH. The first >>> victim of that plan are now 32-bit PV guests, as those are used only >>> rather seldom these days. Xen on x86 requires 64-bit support and with >>> Grub2 now supporting PVH officially since version 2.04 there is no >>> need to keep 32-bit PV guest support alive in the Linux kernel. >>> Additionally Meltdown mitigation is not available in the kernel running >>> as 32-bit PV guest, so dropping this mode makes sense from security >>> point of view, too. >> >> Normally we have a deprecation period for feature removals like this. >> You would make the kernel print a warning for some releases, and when >> no user complains you can then remove. If a user complains you can't. >> > > As I understand it, the kernel rules do allow changes like this even > if there's a complaint: this is a patch that removes what is > effectively hardware support. If the maintenance cost exceeds the > value, then removal is fair game. (Obviously we weight the value to > preserving compatibility quite highly, but in this case, Xen dropped > 32-bit hardware support a long time ago. If the Xen hypervisor says > that 32-bit PV guest support is deprecated, it's deprecated.) Since it was implied but not explicit from Andrew's reply, just to make it explicit: So far 32-bit PV guest support has not been deprecated in Xen itself. Jan ___ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
