Revision 471f0aa7fa64e23766a1473b32d9ec3f0718895a authored by Chang S. Bae on 21 October 2022, 18:58:44 UTC, committed by Dave Hansen on 21 October 2022, 22:22:09 UTC
When an extended state component is not present in fpstate, but in init
state, the function copies from init_fpstate via copy_feature().
But, dynamic states are not present in init_fpstate because of all-zeros
init states. Then retrieving them from init_fpstate will explode like this:
BUG: kernel NULL pointer dereference, address: 0000000000000000
...
RIP: 0010:memcpy_erms+0x6/0x10
? __copy_xstate_to_uabi_buf+0x381/0x870
fpu_copy_guest_fpstate_to_uabi+0x28/0x80
kvm_arch_vcpu_ioctl+0x14c/0x1460 [kvm]
? __this_cpu_preempt_check+0x13/0x20
? vmx_vcpu_put+0x2e/0x260 [kvm_intel]
kvm_vcpu_ioctl+0xea/0x6b0 [kvm]
? kvm_vcpu_ioctl+0xea/0x6b0 [kvm]
? __fget_light+0xd4/0x130
__x64_sys_ioctl+0xe3/0x910
? debug_smp_processor_id+0x17/0x20
? fpregs_assert_state_consistent+0x27/0x50
do_syscall_64+0x3f/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Adjust the 'mask' to zero out the userspace buffer for the features that
are not available both from fpstate and from init_fpstate.
The dynamic features depend on the compacted XSAVE format. Ensure it is
enabled before reading XCOMP_BV in init_fpstate.
Fixes: 2308ee57d93d ("x86/fpu/amx: Enable the AMX feature in 64-bit mode")
Reported-by: Yuan Yao <yuan.yao@intel.com>
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/lkml/BYAPR11MB3717EDEF2351C958F2C86EED95259@BYAPR11MB3717.namprd11.prod.outlook.com/
Link: https://lkml.kernel.org/r/20221021185844.13472-1-chang.seok.bae@intel.com
1 parent b329f5d
| File | Mode | Size |
|---|---|---|
| Makefile | -rw-r--r-- | 366 bytes |
| advise.c | -rw-r--r-- | 2.1 KB |
| advise.h | -rw-r--r-- | 316 bytes |
| alloc_cache.h | -rw-r--r-- | 1.1 KB |
| cancel.c | -rw-r--r-- | 7.2 KB |
| cancel.h | -rw-r--r-- | 579 bytes |
| epoll.c | -rw-r--r-- | 1.5 KB |
| epoll.h | -rw-r--r-- | 213 bytes |
| fdinfo.c | -rw-r--r-- | 6.5 KB |
| fdinfo.h | -rw-r--r-- | 100 bytes |
| filetable.c | -rw-r--r-- | 4.4 KB |
| filetable.h | -rw-r--r-- | 2.5 KB |
| fs.c | -rw-r--r-- | 6.6 KB |
| fs.h | -rw-r--r-- | 929 bytes |
| io-wq.c | -rw-r--r-- | 33.4 KB |
| io-wq.h | -rw-r--r-- | 2.0 KB |
| io_uring.c | -rw-r--r-- | 106.3 KB |
| io_uring.h | -rw-r--r-- | 9.6 KB |
| kbuf.c | -rw-r--r-- | 13.2 KB |
| kbuf.h | -rw-r--r-- | 3.6 KB |
| msg_ring.c | -rw-r--r-- | 4.1 KB |
| msg_ring.h | -rw-r--r-- | 178 bytes |
| net.c | -rw-r--r-- | 35.7 KB |
| net.h | -rw-r--r-- | 2.2 KB |
| nop.c | -rw-r--r-- | 498 bytes |
| nop.h | -rw-r--r-- | 168 bytes |
| notif.c | -rw-r--r-- | 1.8 KB |
| notif.h | -rw-r--r-- | 896 bytes |
| opdef.c | -rw-r--r-- | 11.9 KB |
| opdef.h | -rw-r--r-- | 1.3 KB |
| openclose.c | -rw-r--r-- | 6.1 KB |
| openclose.h | -rw-r--r-- | 596 bytes |
| poll.c | -rw-r--r-- | 25.6 KB |
| poll.h | -rw-r--r-- | 1006 bytes |
| refs.h | -rw-r--r-- | 1.2 KB |
| rsrc.c | -rw-r--r-- | 31.4 KB |
| rsrc.h | -rw-r--r-- | 4.5 KB |
| rw.c | -rw-r--r-- | 27.1 KB |
| rw.h | -rw-r--r-- | 705 bytes |
| slist.h | -rw-r--r-- | 3.0 KB |
| splice.c | -rw-r--r-- | 2.9 KB |
| splice.h | -rw-r--r-- | 306 bytes |
| sqpoll.c | -rw-r--r-- | 9.5 KB |
| sqpoll.h | -rw-r--r-- | 753 bytes |
| statx.c | -rw-r--r-- | 1.6 KB |
| statx.h | -rw-r--r-- | 217 bytes |
| sync.c | -rw-r--r-- | 2.7 KB |
| sync.h | -rw-r--r-- | 460 bytes |
| tctx.c | -rw-r--r-- | 7.2 KB |
| tctx.h | -rw-r--r-- | 992 bytes |
| timeout.c | -rw-r--r-- | 16.6 KB |
| timeout.h | -rw-r--r-- | 1.2 KB |
| uring_cmd.c | -rw-r--r-- | 4.0 KB |
| uring_cmd.h | -rw-r--r-- | 494 bytes |
| xattr.c | -rw-r--r-- | 5.5 KB |
| xattr.h | -rw-r--r-- | 654 bytes |
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