From: Paolo Bonzini Date: Fri, 21 Dec 2018 10:25:59 +0000 (+0100) Subject: KVM: x86: fix size of x86_fpu_cache objects X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=ed8e48122728acfaf7bfa904cba034d83905b43a;p=openwrt%2Fstaging%2Fblogic.git KVM: x86: fix size of x86_fpu_cache objects The memory allocation in b666a4b69739 ("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 --- diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4f786fcc620e..70faa3cdc4dc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -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) {