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Message-Id: <20220426134021.11210-3-jgross@suse.com>
Date: Tue, 26 Apr 2022 15:40:21 +0200
From: Juergen Gross <jgross@...e.com>
To: linux-kernel@...r.kernel.org, x86@...nel.org,
linux-arch@...r.kernel.org, linux-s390@...r.kernel.org,
linux-hyperv@...r.kernel.org,
virtualization@...ts.linux-foundation.org
Cc: Juergen Gross <jgross@...e.com>, Arnd Bergmann <arnd@...db.de>,
Heiko Carstens <hca@...ux.ibm.com>,
Vasily Gorbik <gor@...ux.ibm.com>,
Alexander Gordeev <agordeev@...ux.ibm.com>,
Christian Borntraeger <borntraeger@...ux.ibm.com>,
Sven Schnelle <svens@...ux.ibm.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
"H. Peter Anvin" <hpa@...or.com>,
"K. Y. Srinivasan" <kys@...rosoft.com>,
Haiyang Zhang <haiyangz@...rosoft.com>,
Stephen Hemminger <sthemmin@...rosoft.com>,
Wei Liu <wei.liu@...nel.org>, Dexuan Cui <decui@...rosoft.com>,
Andy Lutomirski <luto@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
"Michael S. Tsirkin" <mst@...hat.com>,
Jason Wang <jasowang@...hat.com>,
Christoph Hellwig <hch@...radead.org>,
Oleksandr Tyshchenko <olekstysh@...il.com>
Subject: [PATCH 2/2] virtio: replace arch_has_restricted_virtio_memory_access()
Instead of using arch_has_restricted_virtio_memory_access() together
with CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS, replace those
with platform_has() and a new platform feature
PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS.
Signed-off-by: Juergen Gross <jgross@...e.com>
---
I've only done a compile test on x86 for now, as I can't test these
changes easily (SEV might be doable for me, but s390 isn't).
---
arch/s390/Kconfig | 1 -
arch/s390/mm/init.c | 13 +++----------
arch/x86/Kconfig | 1 -
arch/x86/kernel/cpu/mshyperv.c | 5 ++++-
arch/x86/mm/mem_encrypt.c | 6 ------
arch/x86/mm/mem_encrypt_identity.c | 5 +++++
drivers/virtio/Kconfig | 6 ------
drivers/virtio/virtio.c | 5 ++---
include/linux/platform-feature.h | 3 ++-
include/linux/virtio_config.h | 9 ---------
10 files changed, 16 insertions(+), 38 deletions(-)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index e084c72104f8..f97a22ae69a8 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -772,7 +772,6 @@ menu "Virtualization"
config PROTECTED_VIRTUALIZATION_GUEST
def_bool n
prompt "Protected virtualization guest support"
- select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
help
Select this option, if you want to be able to run this
kernel as a protected virtualization KVM guest.
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 86ffd0d51fd5..8e4fa10c6b12 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -31,6 +31,7 @@
#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>
@@ -168,22 +169,14 @@ bool force_dma_unencrypted(struct device *dev)
return is_prot_virt_guest();
}
-#ifdef CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
-
-int arch_has_restricted_virtio_memory_access(void)
-{
- return is_prot_virt_guest();
-}
-EXPORT_SYMBOL(arch_has_restricted_virtio_memory_access);
-
-#endif
-
/* protected virtualization */
static void pv_init(void)
{
if (!is_prot_virt_guest())
return;
+ platform_set_feature(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS);
+
/* make sure bounce buffers are shared */
swiotlb_force = SWIOTLB_FORCE;
swiotlb_init(1);
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b0142e01002e..20ac72546ae4 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1515,7 +1515,6 @@ config X86_CPA_STATISTICS
config X86_MEM_ENCRYPT
select ARCH_HAS_FORCE_DMA_UNENCRYPTED
select DYNAMIC_PHYSICAL_MASK
- select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
def_bool n
config AMD_MEM_ENCRYPT
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 4b67094215bb..435611d83895 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -19,6 +19,7 @@
#include <linux/i8253.h>
#include <linux/random.h>
#include <linux/swiotlb.h>
+#include <linux/platform-feature.h>
#include <asm/processor.h>
#include <asm/hypervisor.h>
#include <asm/hyperv-tlfs.h>
@@ -347,8 +348,10 @@ static void __init ms_hyperv_init_platform(void)
#endif
/* Isolation VMs are unenlightened SEV-based VMs, thus this check: */
if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) {
- if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE)
+ if (hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE) {
cc_set_vendor(CC_VENDOR_HYPERV);
+ platform_set_feature(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS);
+ }
}
}
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 50d209939c66..9b6a7c98b2b1 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -76,9 +76,3 @@ void __init mem_encrypt_init(void)
print_mem_encrypt_feature_info();
}
-
-int arch_has_restricted_virtio_memory_access(void)
-{
- return cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT);
-}
-EXPORT_SYMBOL_GPL(arch_has_restricted_virtio_memory_access);
diff --git a/arch/x86/mm/mem_encrypt_identity.c b/arch/x86/mm/mem_encrypt_identity.c
index b43bc24d2bb6..6043ba6cd17d 100644
--- a/arch/x86/mm/mem_encrypt_identity.c
+++ b/arch/x86/mm/mem_encrypt_identity.c
@@ -40,6 +40,7 @@
#include <linux/mm.h>
#include <linux/mem_encrypt.h>
#include <linux/cc_platform.h>
+#include <linux/platform-feature.h>
#include <asm/setup.h>
#include <asm/sections.h>
@@ -566,6 +567,10 @@ void __init sme_enable(struct boot_params *bp)
} else {
/* SEV state cannot be controlled by a command line option */
sme_me_mask = me_mask;
+
+ /* Set restricted memory access for virtio. */
+ platform_set_feature(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS);
+
goto out;
}
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index b5adf6abd241..a6dc8b5846fe 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -6,12 +6,6 @@ config VIRTIO
bus, such as CONFIG_VIRTIO_PCI, CONFIG_VIRTIO_MMIO, CONFIG_RPMSG
or CONFIG_S390_GUEST.
-config ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
- bool
- help
- This option is selected if the architecture may need to enforce
- VIRTIO_F_ACCESS_PLATFORM
-
config VIRTIO_PCI_LIB
tristate
help
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 22f15f444f75..371e16b18381 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -5,6 +5,7 @@
#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. */
@@ -170,12 +171,10 @@ EXPORT_SYMBOL_GPL(virtio_add_status);
static int virtio_features_ok(struct virtio_device *dev)
{
unsigned status;
- int ret;
might_sleep();
- ret = arch_has_restricted_virtio_memory_access();
- if (ret) {
+ if (platform_has(PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS)) {
if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
dev_warn(&dev->dev,
"device must provide VIRTIO_F_VERSION_1\n");
diff --git a/include/linux/platform-feature.h b/include/linux/platform-feature.h
index df393d502a4f..34b649aaa1da 100644
--- a/include/linux/platform-feature.h
+++ b/include/linux/platform-feature.h
@@ -6,7 +6,8 @@
#include <asm/platform-feature.h>
/* The platform features are starting with the architecture specific ones. */
-#define PLATFORM_FEAT_N (0 + PLATFORM_ARCH_FEAT_N)
+#define PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS 0
+#define PLATFORM_FEAT_N (1 + PLATFORM_ARCH_FEAT_N)
#define PLATFORM_FEAT_ARRAY_SZ BITS_TO_LONGS(PLATFORM_FEAT_N)
extern unsigned long platform_features[PLATFORM_FEAT_ARRAY_SZ];
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index b341dd62aa4d..79498298519d 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -559,13 +559,4 @@ static inline void virtio_cwrite64(struct virtio_device *vdev,
_r; \
})
-#ifdef CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
-int arch_has_restricted_virtio_memory_access(void);
-#else
-static inline int arch_has_restricted_virtio_memory_access(void)
-{
- return 0;
-}
-#endif /* CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS */
-
#endif /* _LINUX_VIRTIO_CONFIG_H */
--
2.34.1
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