Hello Stefano, Juergen
On 19.04.22 09:58, Juergen Gross wrote:
On 18.04.22 21:11, Stefano Stabellini wrote:
On Sun, 17 Apr 2022, Oleksandr wrote:
On 16.04.22 01:02, Stefano Stabellini wrote:
On Thu, 14 Apr 2022, Oleksandr Tyshchenko wrote:
From: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
In the context of current patch do the following:
1. Update code to support virtio-mmio devices
2. Introduce struct xen_virtio_data and account passed virtio devices
(using list) as we need to store some per-device data
3. Add multi-page support for xen_virtio_dma_map(unmap)_page
callbacks
4. Harden code against malicious backend
5. Change to use alloc_pages_exact() instead of __get_free_pages()
6. Introduce locking scheme to protect mappings (I am not 100% sure
whether per-device lock is really needed)
7. Handle virtio device's DMA mask
8. Retrieve the ID of backend domain from DT for virtio-mmio device
instead of hardcoding it.
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshche...@epam.com>
---
arch/arm/xen/enlighten.c | 11 +++
drivers/xen/Kconfig | 2 +-
drivers/xen/xen-virtio.c | 200
++++++++++++++++++++++++++++++++++++++++++-----
include/xen/xen-ops.h | 5 ++
4 files changed, 196 insertions(+), 22 deletions(-)
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index ec5b082..870d92f 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -409,6 +409,17 @@ int __init arch_xen_unpopulated_init(struct
resource
**res)
}
#endif
+#ifdef CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
+int arch_has_restricted_virtio_memory_access(void)
+{
+ if (IS_ENABLED(CONFIG_XEN_HVM_VIRTIO_GRANT) && xen_hvm_domain())
+ return 1;
Instead of xen_hvm_domain(), you can just use xen_domain(). Also there
is no need for the #ifdef
CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS, given that:
CONFIG_XEN_HVM_VIRTIO_GRANT depends on XEN_VIRTIO which selects
ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
Yes, but please see my comments in commit #2 regarding
CONFIG_XEN_HVM_VIRTIO_GRANT option and
arch_has_restricted_virtio_memory_access() on Arm.
I propose to have the following on Arm:
int arch_has_restricted_virtio_memory_access(void)
{
return xen_has_restricted_virtio_memory_access();
}
where common xen.h contain a helper to be used by both Arm and x86:
static inline int xen_has_restricted_virtio_memory_access(void)
{
if (IS_ENABLED(CONFIG_XEN_VIRTIO) && (xen_pv_domain() ||
xen_hvm_domain()))
return 1;
return 0;
}
But I would be happy with what you propose as well.
As I wrote in the previous reply, I also prefer to share the code
between x86 and ARM, and I think it could look like:
int arch_has_restricted_virtio_memory_access(void)
{
return xen_has_restricted_virtio_memory_access();
}
[...]
static inline int xen_has_restricted_virtio_memory_access(void)
{
return (IS_ENABLED(CONFIG_XEN_VIRTIO) && xen_domain());
}
But let's check with Juergen and Boris.
for the record, it is already clarified in commit #2, I will use this
variant.
+ return 0;
+}
+EXPORT_SYMBOL_GPL(arch_has_restricted_virtio_memory_access);
+#endif
+
static void __init xen_dt_guest_init(void)
{
struct device_node *xen_node;
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index fc61f7a..56afe6a 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -347,7 +347,7 @@ config XEN_VIRTIO
config XEN_HVM_VIRTIO_GRANT
bool "Require virtio for fully virtualized guests to use grant
mappings"
- depends on XEN_VIRTIO && X86_64
+ depends on XEN_VIRTIO && (X86_64 || ARM || ARM64)
you can remove the architectural dependencies
According to the conversation in commit #2 we are considering just a
single
XEN_VIRTIO option, but it is going to has the
same architectural dependencies: (X86_64 || ARM || ARM64)
By removing the architectural dependencies here, we will leave also
X86_32
covered (neither XEN_HVM_VIRTIO_GRANT nor XEN_PV_VIRTIO covered it).
I don't
know whether it is ok or not.
Shall I remove dependencies anyway?
No, good point. I don't know about X86_32. This is another detail where
Juergen or Boris should comment.
X86_32 should in theory work (it is HVM/PVH only, as PV 32-bit guests
are no
longer supported).
ok, thank you for confirming. I will drop architectural dependencies then.
Juergen
--
Regards,
Oleksandr Tyshchenko
