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Pierre Morel

2020-Aug-31 09:09 UTC

[PATCH v10 0/2] s390: virtio: let arch validate VIRTIO features

Hi all,

The goal of the series is to give a chance to the architecture
to validate VIRTIO device features.

The tests are back to virtio_finalize_features.

No more argument for the architecture callback which only reports
if the architecture needs guest memory access restrictions for
VIRTIO.


I renamed the callback to arch_has_restricted_virtio_memory_access,
and the config option to ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS.

Regards,
Pierre

Pierre Morel (2):
  virtio: let arch advertise guest's memory access restrictions
  s390: virtio: PV needs VIRTIO I/O device protection

 arch/s390/Kconfig             |  1 +
 arch/s390/mm/init.c           | 10 ++++++++++
 drivers/virtio/Kconfig        |  6 ++++++
 drivers/virtio/virtio.c       | 15 +++++++++++++++
 include/linux/virtio_config.h |  9 +++++++++
 5 files changed, 41 insertions(+)

-- 
2.25.1

Changelog

to v10:
- removed virtio_config.h unnecessary include
- wording
  (Connie)

to v9:

- move virtio tests back to virtio_finalize_features
  (Connie)

- remove virtio device argument

to v8:

- refactoring by using an optional callback
  (Connie)

to v7:

- typo in warning message
  (Connie)
to v6:

- rewording warning messages
  (Connie, Halil)

to v5:

- return directly from S390 arch_validate_virtio_features()
  when the guest is not protected.
  (Connie)

- Somme rewording
  (Connie, Michael)

- moved back code from arch/s390/ ...kernel/uv.c to ...mm/init.c
  (Christian)

to v4:

- separate virtio and arch code
  (Pierre)

- moved code from arch/s390/mm/init.c to arch/s390/kernel/uv.c
  (as interpreted from Heiko's comment)

- moved validation inside the arch code
  (Connie)

- moved the call to arch validation before VIRTIO_F_1 test
  (Michael)

to v3:

- add warning
  (Connie, Christian)

- add comment
  (Connie)

- change hook name
  (Halil, Connie)

to v2:

- put the test in virtio_finalize_features()
  (Connie)

- put the test inside VIRTIO core
  (Jason)

- pass a virtio device as parameter
  (Halil)

Pierre Morel

2020-Aug-31 09:09 UTC

head link

[PATCH v10 1/2] virtio: let arch advertise guest's memory access restrictions

An architecture may restrict host access to guest memory,
e.g. IBM s390 Secure Execution or AMD SEV.

Provide a new Kconfig entry the architecture can select,
CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS, when it provides
the arch_has_restricted_virtio_memory_access callback to advertise
to VIRTIO common code when the architecture restricts memory access
from the host.

The common code can then fail the probe for any device where
VIRTIO_F_IOMMU_PLATFORM is required, but not set.

Signed-off-by: Pierre Morel <pmorel at linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck at redhat.com>
---
 drivers/virtio/Kconfig        |  6 ++++++
 drivers/virtio/virtio.c       | 15 +++++++++++++++
 include/linux/virtio_config.h |  9 +++++++++
 3 files changed, 30 insertions(+)

diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index 5809e5f5b157..9cd1c267c143 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -6,6 +6,12 @@ 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_IOMMU_PLATFORM.
+
 menuconfig VIRTIO_MENU
 	bool "Virtio drivers"
 	default y
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index a977e32a88f2..57ca41d77b09 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -176,6 +176,21 @@ int virtio_finalize_features(struct virtio_device *dev)
 	if (ret)
 		return ret;
 
+	ret = arch_has_restricted_virtio_memory_access();
+	if (ret) {
+		if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
+			dev_warn(&dev->dev,
+				 "device must provide VIRTIO_F_VERSION_1\n");
+			return -ENODEV;
+		}
+
+		if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
+			dev_warn(&dev->dev,
+				 "device must provide VIRTIO_F_IOMMU_PLATFORM\n");
+			return -ENODEV;
+		}
+	}
+
 	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
 		return 0;
 
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index bb4cc4910750..e380664642b4 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -459,4 +459,13 @@ 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 */
-- 
2.25.1

Pierre Morel

2020-Aug-31 09:09 UTC

head link

[PATCH v10 2/2] s390: virtio: PV needs VIRTIO I/O device protection

If protected virtualization is active on s390, VIRTIO has only retricted
access to the guest memory.
Define CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS and export
arch_has_restricted_virtio_memory_access to advertize VIRTIO if that's
the case, preventing a host error on access attempt.

Signed-off-by: Pierre Morel <pmorel at linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck at redhat.com>
---
 arch/s390/Kconfig   |  1 +
 arch/s390/mm/init.c | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 9cfd8de907cb..c12422c26389 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -820,6 +820,7 @@ 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 6dc7c3b60ef6..5f289ab1b0d2 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -161,6 +161,16 @@ 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)
 {
-- 
2.25.1

kernel test robot

2020-Aug-31 12:11 UTC

head link

[PATCH v10 2/2] s390: virtio: PV needs VIRTIO I/O device protection

Hi Pierre,

I love your patch! Perhaps something to improve:

[auto build test WARNING on linux/master]
[cannot apply to s390/features linus/master v5.9-rc3 next-20200828]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:   
https://github.com/0day-ci/linux/commits/Pierre-Morel/s390-virtio-let-arch-validate-VIRTIO-features/20200831-171552
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
bcf876870b95592b52519ed4aafcf9d95999bc9c
config: s390-randconfig-r004-20200831 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project
c10e63677f5d20f18010f8f68c631ddc97546f7d)
reproduce (this is a W=1 build):
        wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install s390 cross compiling tool for clang build
        # apt-get install binutils-s390x-linux-gnu
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=s390 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp at intel.com>

All warnings (new ones prefixed by >>):

   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:119:21: note: expanded from macro
'__swab32'
           ___constant_swab32(x) :                 \
                              ^
   include/uapi/linux/swab.h:20:12: note: expanded from macro
'___constant_swab32'
           (((__u32)(x) & (__u32)0x0000ff00UL) <<  8) |            \
                     ^
   In file included from arch/s390/mm/init.c:20:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:22:
   In file included from include/linux/writeback.h:14:
   In file included from include/linux/blk-cgroup.h:23:
   In file included from include/linux/blkdev.h:28:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:490:45: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr));
                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro
'__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:119:21: note: expanded from macro
'__swab32'
           ___constant_swab32(x) :                 \
                              ^
   include/uapi/linux/swab.h:21:12: note: expanded from macro
'___constant_swab32'
           (((__u32)(x) & (__u32)0x00ff0000UL) >>  8) |            \
                     ^
   In file included from arch/s390/mm/init.c:20:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:22:
   In file included from include/linux/writeback.h:14:
   In file included from include/linux/blk-cgroup.h:23:
   In file included from include/linux/blkdev.h:28:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:490:45: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr));
                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro
'__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:119:21: note: expanded from macro
'__swab32'
           ___constant_swab32(x) :                 \
                              ^
   include/uapi/linux/swab.h:22:12: note: expanded from macro
'___constant_swab32'
           (((__u32)(x) & (__u32)0xff000000UL) >> 24)))
                     ^
   In file included from arch/s390/mm/init.c:20:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:22:
   In file included from include/linux/writeback.h:14:
   In file included from include/linux/blk-cgroup.h:23:
   In file included from include/linux/blkdev.h:28:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:490:45: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr));
                                           ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro
'__le32_to_cpu'
   #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
                                                             ^
   include/uapi/linux/swab.h:120:12: note: expanded from macro
'__swab32'
           __fswab32(x))
                     ^
   In file included from arch/s390/mm/init.c:20:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:22:
   In file included from include/linux/writeback.h:14:
   In file included from include/linux/blk-cgroup.h:23:
   In file included from include/linux/blkdev.h:28:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:72:
   include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writeb(value, PCI_IOBASE + addr);
                               ~~~~~~~~~~ ^
   include/asm-generic/io.h:511:46: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writew(cpu_to_le16(value), PCI_IOBASE + addr);
                                            ~~~~~~~~~~ ^
   include/asm-generic/io.h:521:46: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           __raw_writel(cpu_to_le32(value), PCI_IOBASE + addr);
                                            ~~~~~~~~~~ ^
   include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsb(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsw(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           readsl(PCI_IOBASE + addr, buffer, count);
                  ~~~~~~~~~~ ^
   include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesb(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesw(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^
   include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a
null pointer has undefined behavior [-Wnull-pointer-arithmetic]
           writesl(PCI_IOBASE + addr, buffer, count);
                   ~~~~~~~~~~ ^>> arch/s390/mm/init.c:166:5: warning: no previous prototype for function
'arch_has_restricted_virtio_memory_access' [-Wmissing-prototypes]   int arch_has_restricted_virtio_memory_access(void)
       ^
   arch/s390/mm/init.c:166:1: note: declare 'static' if the function is
not intended to be used outside of this translation unit
   int arch_has_restricted_virtio_memory_access(void)
   ^
   static 
   In file included from arch/s390/mm/init.c:11:
   In file included from include/linux/signal.h:5:
   In file included from include/linux/bug.h:5:
   In file included from arch/s390/include/asm/bug.h:5:
   In file included from include/linux/kernel.h:12:
   In file included from include/linux/bitops.h:29:
   arch/s390/include/asm/bitops.h:69:4: error: invalid operand in inline asm:
'oi	$0,${1:b}'
                           "oi     %0,%b1\n"
                           ^
   arch/s390/include/asm/bitops.h:69:4: error: invalid operand in inline asm:
'oi	$0,${1:b}'
   arch/s390/include/asm/bitops.h:69:4: error: invalid operand in inline asm:
'oi	$0,${1:b}'
   21 warnings and 3 errors generated.

#
https://github.com/0day-ci/linux/commit/76e649717b36f092b03739629b7a036fcc383ee1
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review
Pierre-Morel/s390-virtio-let-arch-validate-VIRTIO-features/20200831-171552
git checkout 76e649717b36f092b03739629b7a036fcc383ee1
vim +/arch_has_restricted_virtio_memory_access +166 arch/s390/mm/init.c

   165	
 > 166	int arch_has_restricted_virtio_memory_access(void)
   167	{
   168		return is_prot_virt_guest();
   169	}
   170	EXPORT_SYMBOL(arch_has_restricted_virtio_memory_access);
   171	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all at lists.01.org
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