Messages in this thread Patch in this message | | | From | Yang Zhong <> | Subject | [PATCH] x86/fpu: Set the corret permission value for perm.__state_perm | Date | Mon, 8 Nov 2021 17:28:15 -0500 |
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The perm.__state_perm is default xsave set features, when we request AMX permission from application, the requested value(bit18) should be replaced with mask value(requested | permitted), which can keep default features there.
Without this change, the below prctl syscall: (1). ARCH_GET_XCOMP_PERM, the bitmask=0x202e7 (2). set ARCH_REQ_XCOMP_PERM with XFEATURE_XTILEDATA (3). ARCH_GET_XCOMP_PERM, the bitmask=0x40000, the correct value should be 0x602e7 here.
Signed-off-by: Yang Zhong <yang.zhong@intel.com> --- arch/x86/kernel/fpu/xstate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index d28829403ed0..fc1ab0116f4e 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1626,7 +1626,7 @@ static int __xstate_request_perm(u64 permitted, u64 requested) return ret; /* Pairs with the READ_ONCE() in xstate_get_group_perm() */ - WRITE_ONCE(fpu->perm.__state_perm, requested); + WRITE_ONCE(fpu->perm.__state_perm, mask); /* Protected by sighand lock */ fpu->perm.__state_size = ksize; fpu->perm.__user_state_size = usize; -- 2.30.2
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