Commit a603002e authored by Juergen Gross's avatar Juergen Gross
Browse files

virtio: replace restricted mem access flag with callback 



Instead of having a global flag to require restricted memory access
for all virtio devices, introduce a callback which can select that
requirement on a per-device basis.

For convenience add a common function returning always true, which can
be used for use cases like SEV.

Per default use a callback always returning false.

As the callback needs to be set in early init code already, add a
virtio anchor which is builtin in case virtio is enabled.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Tested-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> # Arm64 guest using Xen
Reviewed-by: default avatarStefano Stabellini <sstabellini@kernel.org>
Link: https://lore.kernel.org/r/20220622063838.8854-2-jgross@suse.com


Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 8441dac0

arch/s390/mm/init.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

arch/x86/mm/mem_encrypt_amd.c

+2 −2
Original line number Diff line number Diff line
@@ -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)

drivers/virtio/Kconfig

+4 −0
Original line number Diff line number Diff line 
# 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

drivers/virtio/Makefile

+1 −0
Original line number Diff line number Diff line 
# 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

drivers/virtio/virtio.c

+2 −2
Original line number Diff line number Diff line
@@ -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");