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KVM: x86: fix size of x86_fpu_cache objects 

The memory allocation in b666a4b697 ("kvm: x86: Dynamically allocate
guest_fpu", 2018-11-06) is wrong, there are other members in struct fpu
before the fpregs_state union and the patch should be doing something
similar to the code in fpu__init_task_struct_size.  It's enough to run
a guest and then rmmod kvm to see slub errors which are actually caused
by memory corruption.

For now let's revert it to sizeof(struct fpu), which is conservative.
I have plans to move fsave/fxsave/xsave directly in KVM, without using
the kernel FPU helpers, and once it's done, the size of the object in
the cache will be something like kvm_xstate_size.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
hifive-unleashed-5.1
Paolo Bonzini 2018-12-21 11:25:59 +01:00
parent cfdfaf4a86
commit ed8e481227
1 changed files with 1 additions and 1 deletions
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2
arch/x86/kvm/x86.c
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@ -6867,7 +6867,7 @@ int kvm_arch_init(void *opaque)
}
r = -ENOMEM;
x86_fpu_cache = kmem_cache_create("x86_fpu", fpu_kernel_xstate_size,
x86_fpu_cache = kmem_cache_create("x86_fpu", sizeof(struct fpu),
__alignof__(struct fpu), SLAB_ACCOUNT,
NULL);
if (!x86_fpu_cache) {