kernel.git/arch/s390/kernel/uv.c, branch linux-5.13.y

s390: mm: Fix secure storage access exception handling

2021-07-14T15:06:13Z

commit 85b18d7b5e7ffefb2f076186511d39c4990aa005 upstream. Turns out that the bit 61 in the TEID is not always 1 and if that's the case the address space ID and the address are unpredictable. Without an address and its address space ID we can't export memory and hence we can only send a SIGSEGV to the process or panic the kernel depending on who caused the exception. Unfortunately bit 61 is only reliable if we have the "misc" UV feature bit. Signed-off-by: Janosch Frank Reviewed-by: Christian Borntraeger Fixes: 084ea4d611a3d ("s390/mm: add (non)secure page access exceptions handlers") Cc: stable@vger.kernel.org Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/protvirt: fix error return code in uv_info_init()

2021-04-12T10:46:41Z

Fix to return a negative error code from the error handling case instead of 0, as done elsewhere in this function. Reported-by: Hulk Robot Signed-off-by: Baisong Zhong Fixes: 37564ed834ac ("s390/uv: add prot virt guest/host indication files") Link: https://lore.kernel.org/r/2f7d62a4-3e75-b2b4-951b-75ef8ef59d16@huawei.com Signed-off-by: Heiko Carstens

s390/uv: fix prot virt host indication compilation

2021-03-24T15:06:19Z

prot_virt_host is only available if CONFIG_KVM is enabled. So lets use a variable initialized to zero and overwrite it when that config option is set with prot_virt_host. Signed-off-by: Janosch Frank Fixes: 37564ed834ac ("s390/uv: add prot virt guest/host indication files") Reported-by: kernel test robot Signed-off-by: Heiko Carstens

s390/uv: add prot virt guest/host indication files

2021-03-22T10:36:03Z

Let's export the prot_virt_guest and prot_virt_host variables into the UV sysfs firmware interface to make them easily consumable by administrators. prot_virt_host being 1 indicates that we did the UV initialization (opt-in) prot_virt_guest being 1 indicates that the UV indicates the share and unshare ultravisor calls which is an indication that we are running as a protected guest. Signed-off-by: Janosch Frank Acked-by: Christian Borntraeger Signed-off-by: Heiko Carstens

s390: uv: Fix sysfs max number of VCPUs reporting

2021-01-27T12:00:04Z

The number reported by the query is N-1 and I think people reading the sysfs file would expect N instead. For users creating VMs there's no actual difference because KVM's limit is currently below the UV's limit. Signed-off-by: Janosch Frank Fixes: a0f60f8431999 ("s390/protvirt: Add sysfs firmware interface for Ultravisor information") Cc: stable@vger.kernel.org Reviewed-by: Claudio Imbrenda Acked-by: Cornelia Huck Signed-off-by: Vasily Gorbik

s390/uv: handle destroy page legacy interface

2020-11-18T12:08:49Z

Older firmware can return rc=0x107 rrc=0xd for destroy page if the page is already non-secure. This should be handled like a success as already done by newer firmware. Signed-off-by: Christian Borntraeger Fixes: 1a80b54d1ce1 ("s390/uv: add destroy page call") Reviewed-by: David Hildenbrand Acked-by: Cornelia Huck Reviewed-by: Janosch Frank

s390/kasan: support protvirt with 4-level paging

2020-09-16T12:08:48Z

Currently the kernel crashes in Kasan instrumentation code if CONFIG_KASAN_S390_4_LEVEL_PAGING is used on protected virtualization capable machine where the ultravisor imposes addressing limitations on the host and those limitations are lower then KASAN_SHADOW_OFFSET. The problem is that Kasan has to know in advance where vmalloc/modules areas would be. With protected virtualization enabled vmalloc/modules areas are moved down to the ultravisor secure storage limit while kasan still expects them at the very end of 4-level paging address space. To fix that make Kasan recognize when protected virtualization is enabled and predefine vmalloc/modules areas position which are compliant with ultravisor secure storage limit. Kasan shadow itself stays in place and might reside above that ultravisor secure storage limit. One slight difference compaired to a kernel without Kasan enabled is that vmalloc/modules areas position is not reverted to default if ultravisor initialization fails. It would still be below the ultravisor secure storage limit. Kernel layout with kasan, 4-level paging and protected virtualization enabled (ultravisor secure storage limit is at 0x0000800000000000): ---[ vmemmap Area Start ]--- 0x0000400000000000-0x0000400080000000 ---[ vmemmap Area End ]--- ---[ vmalloc Area Start ]--- 0x00007fe000000000-0x00007fff80000000 ---[ vmalloc Area End ]--- ---[ Modules Area Start ]--- 0x00007fff80000000-0x0000800000000000 ---[ Modules Area End ]--- ---[ Kasan Shadow Start ]--- 0x0018000000000000-0x001c000000000000 ---[ Kasan Shadow End ]--- 0x001c000000000000-0x0020000000000000 1P PGD I Kernel layout with kasan, 4-level paging and protected virtualization disabled/unsupported: ---[ vmemmap Area Start ]--- 0x0000400000000000-0x0000400060000000 ---[ vmemmap Area End ]--- ---[ Kasan Shadow Start ]--- 0x0018000000000000-0x001c000000000000 ---[ Kasan Shadow End ]--- ---[ vmalloc Area Start ]--- 0x001fffe000000000-0x001fffff80000000 ---[ vmalloc Area End ]--- ---[ Modules Area Start ]--- 0x001fffff80000000-0x0020000000000000 ---[ Modules Area End ]--- Signed-off-by: Vasily Gorbik

s390/protvirt: support ultravisor without secure storage limit

2020-09-16T12:08:47Z

Avoid potential crash due to lack of secure storage limit. Check that max_sec_stor_addr is not 0 before adjusting vmalloc position. Signed-off-by: Vasily Gorbik

s390/protvirt: parse prot_virt option in the decompressor

2020-09-16T12:08:47Z

To make early kernel address space layout definition possible parse prot_virt option in the decompressor and pass it to the uncompressed kernel. This enables kasan to take ultravisor secure storage limit into consideration and pre-define vmalloc position correctly. Signed-off-by: Vasily Gorbik

s390/uv: add destroy page call

2020-09-14T09:38:35Z

We don't need to export pages if we destroy the VM configuration afterwards anyway. Instead we can destroy the page which will zero it and then make it accessible to the host. Destroying is about twice as fast as the export. Signed-off-by: Janosch Frank Reviewed-by: Claudio Imbrenda Reviewed-by: Thomas Huth Reviewed-by: Cornelia Huck Link: https://lore.kernel.org/kvm/20200907124700.10374-2-frankja@linux.ibm.com/ Signed-off-by: Janosch Frank Signed-off-by: Vasily Gorbik