[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v2] xen: don't require virtio with grants for non-PV guests
On Thu, Jun 16, 2022 at 07:37:15AM +0200, Juergen Gross wrote: > Commit fa1f57421e0b ("xen/virtio: Enable restricted memory access using > Xen grant mappings") introduced a new requirement for using virtio > devices: the backend now needs to support the VIRTIO_F_ACCESS_PLATFORM > feature. > > This is an undue requirement for non-PV guests, as those can be operated > with existing backends without any problem, as long as those backends > are running in dom0. > > Per default allow virtio devices without grant support for non-PV > guests. > > Add a new config item to always force use of grants for virtio. What Í'd really expect here is to only set the limitations for the actual grant-based devic. Unfortunately PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS is global instead of per-device, but this is what coms closest to that intention without major refactoring: diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index 1f9c3ba328333..07eb69f9e7df3 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -443,8 +443,6 @@ static int __init xen_guest_init(void) if (!xen_domain()) return 0; - xen_set_restricted_virtio_memory_access(); - if (!acpi_disabled) xen_acpi_guest_init(); else diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c index 8b71b1dd76396..517a9d8d8f94d 100644 --- a/arch/x86/xen/enlighten_hvm.c +++ b/arch/x86/xen/enlighten_hvm.c @@ -195,8 +195,6 @@ static void __init xen_hvm_guest_init(void) if (xen_pv_domain()) return; - xen_set_restricted_virtio_memory_access(); - init_hvm_pv_info(); reserve_shared_info(); diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index e3297b15701c6..f33a4421e7cd6 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -109,8 +109,6 @@ static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc); static void __init xen_pv_init_platform(void) { - xen_set_restricted_virtio_memory_access(); - populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP)); set_fixmap(FIX_PARAVIRT_BOOTMAP, xen_start_info->shared_info); diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c index fc01424840017..f9bbacb5b5456 100644 --- a/drivers/xen/grant-dma-ops.c +++ b/drivers/xen/grant-dma-ops.c @@ -8,6 +8,7 @@ */ #include <linux/module.h> +#include <linux/platform-feature.h> #include <linux/dma-map-ops.h> #include <linux/of.h> #include <linux/pfn.h> @@ -333,6 +334,8 @@ void xen_grant_setup_dma_ops(struct device *dev) goto err; } + /* XXX: this really should be per-device instead of blobal */ + platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS); dev->dma_ops = &xen_grant_dma_ops; return; diff --git a/include/xen/xen.h b/include/xen/xen.h index 0780a81e140de..a99bab8175234 100644 --- a/include/xen/xen.h +++ b/include/xen/xen.h @@ -52,14 +52,6 @@ bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, extern u64 xen_saved_max_mem_size; #endif -#include <linux/platform-feature.h> - -static inline void xen_set_restricted_virtio_memory_access(void) -{ - if (IS_ENABLED(CONFIG_XEN_VIRTIO) && xen_domain()) - platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS); -} - #ifdef CONFIG_XEN_UNPOPULATED_ALLOC int xen_alloc_unpopulated_pages(unsigned int nr_pages, struct page **pages); void xen_free_unpopulated_pages(unsigned int nr_pages, struct page **pages);
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