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. > > > + 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.