diff --git a/MAINTAINERS b/MAINTAINERS
index 1d3f149297a7..a9f77648c107 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -16121,14 +16121,6 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.yaml
 F:	drivers/iio/chemical/pms7003.c
 
-PLATFORM FEATURE INFRASTRUCTURE
-M:	Juergen Gross <jgross@suse.com>
-S:	Maintained
-F:	arch/*/include/asm/platform-feature.h
-F:	include/asm-generic/platform-feature.h
-F:	include/linux/platform-feature.h
-F:	kernel/platform-feature.c
-
 PLDMFW LIBRARY
 M:	Jacob Keller <jacob.e.keller@intel.com>
 S:	Maintained
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 1f9c3ba32833..93c8ccbf2982 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -34,6 +34,7 @@
 #include <linux/timekeeping.h>
 #include <linux/timekeeper_internal.h>
 #include <linux/acpi.h>
+#include <linux/virtio_anchor.h>
 
 #include <linux/mm.h>
 
@@ -443,7 +444,8 @@ static int __init xen_guest_init(void)
 	if (!xen_domain())
 		return 0;
 
-	xen_set_restricted_virtio_memory_access();
+	if (IS_ENABLED(CONFIG_XEN_VIRTIO))
+		virtio_set_mem_acc_cb(xen_virtio_mem_acc);
 
 	if (!acpi_disabled)
 		xen_acpi_guest_init();
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 6a0ac00d5a42..4a154a084966 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -31,7 +31,6 @@
 #include <linux/cma.h>
 #include <linux/gfp.h>
 #include <linux/dma-direct.h>
-#include <linux/platform-feature.h>
 #include <asm/processor.h>
 #include <linux/uaccess.h>
 #include <asm/pgalloc.h>
@@ -48,6 +47,7 @@
 #include <asm/kasan.h>
 #include <asm/dma-mapping.h>
 #include <asm/uv.h>
+#include <linux/virtio_anchor.h>
 #include <linux/virtio_config.h>
 
 pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(".bss..swapper_pg_dir");
@@ -175,7 +175,7 @@ static void pv_init(void)
 	if (!is_prot_virt_guest())
 		return;
 
-	platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS);
+	virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
 
 	/* make sure bounce buffers are shared */
 	swiotlb_init(true, SWIOTLB_FORCE | SWIOTLB_VERBOSE);
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index f6d038e2cd8e..97452688f99f 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -20,8 +20,8 @@
 #include <linux/bitops.h>
 #include <linux/dma-mapping.h>
 #include <linux/virtio_config.h>
+#include <linux/virtio_anchor.h>
 #include <linux/cc_platform.h>
-#include <linux/platform-feature.h>
 
 #include <asm/tlbflush.h>
 #include <asm/fixmap.h>
@@ -245,7 +245,7 @@ void __init sev_setup_arch(void)
 	swiotlb_adjust_size(size);
 
 	/* Set restricted memory access for virtio. */
-	platform_set(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS);
+	virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
 }
 
 static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index 8b71b1dd7639..28762f800596 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -4,6 +4,7 @@
 #include <linux/cpu.h>
 #include <linux/kexec.h>
 #include <linux/memblock.h>
+#include <linux/virtio_anchor.h>
 
 #include <xen/features.h>
 #include <xen/events.h>
@@ -195,7 +196,8 @@ static void __init xen_hvm_guest_init(void)
 	if (xen_pv_domain())
 		return;
 
-	xen_set_restricted_virtio_memory_access();
+	if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT))
+		virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
 
 	init_hvm_pv_info();
 
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 70fb2ea85e90..0ed2e487a693 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -31,6 +31,7 @@
 #include <linux/gfp.h>
 #include <linux/edd.h>
 #include <linux/reboot.h>
+#include <linux/virtio_anchor.h>
 
 #include <xen/xen.h>
 #include <xen/events.h>
@@ -109,7 +110,9 @@ static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
 
 static void __init xen_pv_init_platform(void)
 {
-	xen_set_restricted_virtio_memory_access();
+	/* PV guests can't operate virtio devices without grants. */
+	if (IS_ENABLED(CONFIG_XEN_VIRTIO))
+		virtio_set_mem_acc_cb(virtio_require_restricted_mem_acc);
 
 	populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
 
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index e1556d2a355a..56c77f63cd22 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -1,6 +1,10 @@
 # SPDX-License-Identifier: GPL-2.0-only
+config VIRTIO_ANCHOR
+	bool
+
 config VIRTIO
 	tristate
+	select VIRTIO_ANCHOR
 	help
 	  This option is selected by any driver which implements the virtio
 	  bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG
diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
index 0a82d0873248..8e98d24917cc 100644
--- a/drivers/virtio/Makefile
+++ b/drivers/virtio/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_VIRTIO) += virtio.o virtio_ring.o
+obj-$(CONFIG_VIRTIO_ANCHOR) += virtio_anchor.o
 obj-$(CONFIG_VIRTIO_PCI_LIB) += virtio_pci_modern_dev.o
 obj-$(CONFIG_VIRTIO_PCI_LIB_LEGACY) += virtio_pci_legacy_dev.o
 obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 7deeed30d1f3..14c142d77fba 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -2,10 +2,10 @@
 #include <linux/virtio.h>
 #include <linux/spinlock.h>
 #include <linux/virtio_config.h>
+#include <linux/virtio_anchor.h>
 #include <linux/module.h>
 #include <linux/idr.h>
 #include <linux/of.h>
-#include <linux/platform-feature.h>
 #include <uapi/linux/virtio_ids.h>
 
 /* Unique numbering for virtio devices. */
@@ -174,7 +174,7 @@ static int virtio_features_ok(struct virtio_device *dev)
 
 	might_sleep();
 
-	if (platform_has(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS)) {
+	if (virtio_check_mem_acc_cb(dev)) {
 		if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
 			dev_warn(&dev->dev,
 				 "device must provide VIRTIO_F_VERSION_1\n");
diff --git a/drivers/virtio/virtio_anchor.c b/drivers/virtio/virtio_anchor.c
new file mode 100644
index 000000000000..4d6a5d269b55
--- /dev/null
+++ b/drivers/virtio/virtio_anchor.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/virtio.h>
+#include <linux/virtio_anchor.h>
+
+bool virtio_require_restricted_mem_acc(struct virtio_device *dev)
+{
+	return true;
+}
+EXPORT_SYMBOL_GPL(virtio_require_restricted_mem_acc);
+
+static bool virtio_no_restricted_mem_acc(struct virtio_device *dev)
+{
+	return false;
+}
+
+bool (*virtio_check_mem_acc_cb)(struct virtio_device *dev) =
+	virtio_no_restricted_mem_acc;
+EXPORT_SYMBOL_GPL(virtio_check_mem_acc_cb);
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index bfd5f4f706bc..a65bd92121a5 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -355,4 +355,13 @@ config XEN_VIRTIO
 
 	  If in doubt, say n.
 
+config XEN_VIRTIO_FORCE_GRANT
+	bool "Require Xen virtio support to use grants"
+	depends on XEN_VIRTIO
+	help
+	  Require virtio for Xen guests to use grant mappings.
+	  This will avoid the need to give the backend the right to map all
+	  of the guest memory. This will need support on the backend side
+	  (e.g. qemu or kernel, depending on the virtio device types used).
+
 endmenu
diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
index fc0142484001..8973fc1e9ccc 100644
--- a/drivers/xen/grant-dma-ops.c
+++ b/drivers/xen/grant-dma-ops.c
@@ -12,6 +12,8 @@
 #include <linux/of.h>
 #include <linux/pfn.h>
 #include <linux/xarray.h>
+#include <linux/virtio_anchor.h>
+#include <linux/virtio.h>
 #include <xen/xen.h>
 #include <xen/xen-ops.h>
 #include <xen/grant_table.h>
@@ -287,6 +289,14 @@ bool xen_is_grant_dma_device(struct device *dev)
 	return has_iommu;
 }
 
+bool xen_virtio_mem_acc(struct virtio_device *dev)
+{
+	if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT))
+		return true;
+
+	return xen_is_grant_dma_device(dev->dev.parent);
+}
+
 void xen_grant_setup_dma_ops(struct device *dev)
 {
 	struct xen_grant_dma_data *data;
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index 3d5a384d65f7..c16df629907e 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -205,7 +205,7 @@ static void do_poweroff(void)
 static void do_reboot(void)
 {
 	shutting_down = SHUTDOWN_POWEROFF; /* ? */
-	ctrl_alt_del();
+	orderly_reboot();
 }
 
 static struct shutdown_handler shutdown_handlers[] = {
diff --git a/drivers/xen/xen-front-pgdir-shbuf.c b/drivers/xen/xen-front-pgdir-shbuf.c
index bef8d72a6ca6..5c0b5cb5b419 100644
--- a/drivers/xen/xen-front-pgdir-shbuf.c
+++ b/drivers/xen/xen-front-pgdir-shbuf.c
@@ -89,7 +89,7 @@ EXPORT_SYMBOL_GPL(xen_front_pgdir_shbuf_get_dir_start);
  * shared by the frontend itself) or map the provided granted
  * references onto the backing storage (buf->pages).
  *
- * \param buf shared buffer which grants to be maped.
+ * \param buf shared buffer which grants to be mapped.
  * \return zero on success or a negative number on failure.
  */
 int xen_front_pgdir_shbuf_map(struct xen_front_pgdir_shbuf *buf)
@@ -110,7 +110,7 @@ EXPORT_SYMBOL_GPL(xen_front_pgdir_shbuf_map);
  * shared by the frontend itself) or unmap the provided granted
  * references.
  *
- * \param buf shared buffer which grants to be unmaped.
+ * \param buf shared buffer which grants to be unmapped.
  * \return zero on success or a negative number on failure.
  */
 int xen_front_pgdir_shbuf_unmap(struct xen_front_pgdir_shbuf *buf)
diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild
index 36db8b9eb68a..941be574bbe0 100644
--- a/include/asm-generic/Kbuild
+++ b/include/asm-generic/Kbuild
@@ -45,7 +45,6 @@ mandatory-y += msi.h
 mandatory-y += pci.h
 mandatory-y += percpu.h
 mandatory-y += pgalloc.h
-mandatory-y += platform-feature.h
 mandatory-y += preempt.h
 mandatory-y += rwonce.h
 mandatory-y += sections.h
diff --git a/include/asm-generic/platform-feature.h b/include/asm-generic/platform-feature.h
deleted file mode 100644
index 4b0af3d51588..000000000000
--- a/include/asm-generic/platform-feature.h
+++ /dev/null
@@ -1,8 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_GENERIC_PLATFORM_FEATURE_H
-#define _ASM_GENERIC_PLATFORM_FEATURE_H
-
-/* Number of arch specific feature flags. */
-#define PLATFORM_ARCH_FEAT_N	0
-
-#endif /* _ASM_GENERIC_PLATFORM_FEATURE_H */
diff --git a/include/linux/platform-feature.h b/include/linux/platform-feature.h
deleted file mode 100644
index b2f48be999fa..000000000000
--- a/include/linux/platform-feature.h
+++ /dev/null
@@ -1,19 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _PLATFORM_FEATURE_H
-#define _PLATFORM_FEATURE_H
-
-#include <linux/bitops.h>
-#include <asm/platform-feature.h>
-
-/* The platform features are starting with the architecture specific ones. */
-
-/* Used to enable platform specific DMA handling for virtio devices. */
-#define PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS	(0 + PLATFORM_ARCH_FEAT_N)
-
-#define PLATFORM_FEAT_N				(1 + PLATFORM_ARCH_FEAT_N)
-
-void platform_set(unsigned int feature);
-void platform_clear(unsigned int feature);
-bool platform_has(unsigned int feature);
-
-#endif /* _PLATFORM_FEATURE_H */
diff --git a/include/linux/virtio_anchor.h b/include/linux/virtio_anchor.h
new file mode 100644
index 000000000000..432e6c00b3ca
--- /dev/null
+++ b/include/linux/virtio_anchor.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_VIRTIO_ANCHOR_H
+#define _LINUX_VIRTIO_ANCHOR_H
+
+#ifdef CONFIG_VIRTIO_ANCHOR
+struct virtio_device;
+
+bool virtio_require_restricted_mem_acc(struct virtio_device *dev);
+extern bool (*virtio_check_mem_acc_cb)(struct virtio_device *dev);
+
+static inline void virtio_set_mem_acc_cb(bool (*func)(struct virtio_device *))
+{
+	virtio_check_mem_acc_cb = func;
+}
+#else
+#define virtio_set_mem_acc_cb(func) do { } while (0)
+#endif
+
+#endif /* _LINUX_VIRTIO_ANCHOR_H */
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index 80546960f8b7..dae0f350c678 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -5,6 +5,7 @@
 #include <linux/percpu.h>
 #include <linux/notifier.h>
 #include <linux/efi.h>
+#include <linux/virtio_anchor.h>
 #include <xen/features.h>
 #include <asm/xen/interface.h>
 #include <xen/interface/vcpu.h>
@@ -217,6 +218,7 @@ static inline void xen_preemptible_hcall_end(void) { }
 #ifdef CONFIG_XEN_GRANT_DMA_OPS
 void xen_grant_setup_dma_ops(struct device *dev);
 bool xen_is_grant_dma_device(struct device *dev);
+bool xen_virtio_mem_acc(struct virtio_device *dev);
 #else
 static inline void xen_grant_setup_dma_ops(struct device *dev)
 {
@@ -225,6 +227,13 @@ static inline bool xen_is_grant_dma_device(struct device *dev)
 {
 	return false;
 }
+
+struct virtio_device;
+
+static inline bool xen_virtio_mem_acc(struct virtio_device *dev)
+{
+	return false;
+}
 #endif /* CONFIG_XEN_GRANT_DMA_OPS */
 
 #endif /* INCLUDE_XEN_OPS_H */
diff --git a/include/xen/xen.h b/include/xen/xen.h
index 0780a81e140d..a99bab817523 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);
diff --git a/kernel/Makefile b/kernel/Makefile
index a7e1f49ab2b3..318789c728d3 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -7,7 +7,7 @@ obj-y     = fork.o exec_domain.o panic.o \
 	    cpu.o exit.o softirq.o resource.o \
 	    sysctl.o capability.o ptrace.o user.o \
 	    signal.o sys.o umh.o workqueue.o pid.o task_work.o \
-	    extable.o params.o platform-feature.o \
+	    extable.o params.o \
 	    kthread.o sys_ni.o nsproxy.o \
 	    notifier.o ksysfs.o cred.o reboot.o \
 	    async.o range.o smpboot.o ucount.o regset.o
diff --git a/kernel/platform-feature.c b/kernel/platform-feature.c
deleted file mode 100644
index cb6a6c3e4fed..000000000000
--- a/kernel/platform-feature.c
+++ /dev/null
@@ -1,27 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-#include <linux/bitops.h>
-#include <linux/cache.h>
-#include <linux/export.h>
-#include <linux/platform-feature.h>
-
-#define PLATFORM_FEAT_ARRAY_SZ  BITS_TO_LONGS(PLATFORM_FEAT_N)
-static unsigned long __read_mostly platform_features[PLATFORM_FEAT_ARRAY_SZ];
-
-void platform_set(unsigned int feature)
-{
-	set_bit(feature, platform_features);
-}
-EXPORT_SYMBOL_GPL(platform_set);
-
-void platform_clear(unsigned int feature)
-{
-	clear_bit(feature, platform_features);
-}
-EXPORT_SYMBOL_GPL(platform_clear);
-
-bool platform_has(unsigned int feature)
-{
-	return test_bit(feature, platform_features);
-}
-EXPORT_SYMBOL_GPL(platform_has);