From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, "Andy Lutomirski" <luto@kernel.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
kvm@vger.kernel.org, "Jason A. Donenfeld" <Jason@zx2c4.com>,
"Rik van Riel" <riel@surriel.com>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>
Subject: [RFC PATCH 09/10] x86/fpu: copy non-resident FPU state at fork time
Date: Wed, 12 Sep 2018 15:33:52 +0200 [thread overview]
Message-ID: <20180912133353.20595-10-bigeasy@linutronix.de> (raw)
In-Reply-To: <20180912133353.20595-1-bigeasy@linutronix.de>
From: Rik van Riel <riel@surriel.com>
If the FPU state is not loaded in registers at fork time, memcpy the
fpstate from the parent task to the child task.
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
arch/x86/kernel/fpu/core.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 2ea85b32421a0..8564086c217fc 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -210,11 +210,14 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu)
* ( The function 'fails' in the FNSAVE case, which destroys
* register contents so we have to copy them back. )
*/
- if (!copy_fpregs_to_fpstate(dst_fpu)) {
+ __fpregs_changes_begin();
+ if (test_thread_flag(TIF_LOAD_FPU)) {
+ memcpy(&src_fpu->state, &dst_fpu->state, fpu_kernel_xstate_size);
+ } else if (!copy_fpregs_to_fpstate(dst_fpu)) {
memcpy(&src_fpu->state, &dst_fpu->state, fpu_kernel_xstate_size);
copy_kernel_to_fpregs(&src_fpu->state);
}
-
+ __fpregs_changes_end();
trace_x86_fpu_copy_src(src_fpu);
trace_x86_fpu_copy_dst(dst_fpu);
--
2.19.0
next prev parent reply other threads:[~2018-09-12 13:36 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-12 13:33 [RFC PATCH] x86: load FPU registers on return to userland Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 01/10] x86/entry: remove _TIF_ALLWORK_MASK Sebastian Andrzej Siewior
2018-09-27 14:21 ` Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 02/10] kvm: x86: make kvm_{load|put}_guest_fpu() static Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 03/10] x86/fpu: add (__)make_fpregs_active helpers Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 04/10] x86/fpu: eager switch PKRU state Sebastian Andrzej Siewior
2018-09-12 14:18 ` Paolo Bonzini
2018-09-12 15:24 ` Andy Lutomirski
2018-09-12 15:30 ` Paolo Bonzini
2018-09-14 20:35 ` [RFC PATCH 04/10 v2 ] " Sebastian Andrzej Siewior
2018-09-17 8:37 ` Paolo Bonzini
2018-09-18 14:27 ` Sebastian Andrzej Siewior
2018-09-18 15:07 ` Paolo Bonzini
2018-09-18 15:11 ` Rik van Riel
2018-09-18 15:29 ` Paolo Bonzini
2018-09-18 16:04 ` Sebastian Andrzej Siewior
2018-09-18 17:29 ` Rik van Riel
2018-09-19 5:55 ` Paolo Bonzini
2018-09-19 16:57 ` Sebastian Andrzej Siewior
2018-09-19 17:00 ` Paolo Bonzini
2018-09-19 17:19 ` Sebastian Andrzej Siewior
2018-09-19 19:38 ` Rik van Riel
2018-09-19 19:49 ` Andy Lutomirski
2018-09-12 15:20 ` [RFC PATCH 04/10] " Andy Lutomirski
2018-09-12 15:30 ` Rik van Riel
2018-09-12 15:49 ` Andy Lutomirski
2018-09-19 16:58 ` Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 05/10] x86/pkeys: Drop the preempt-disable section Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 06/10] x86/fpu: Always store the registers in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 07/10] x86/entry: add TIF_LOAD_FPU Sebastian Andrzej Siewior
2018-09-12 13:33 ` [RFC PATCH 08/10] x86/fpu: prepare copy_fpstate_to_sigframe for TIF_LOAD_FPU Sebastian Andrzej Siewior
2018-09-12 13:33 ` Sebastian Andrzej Siewior [this message]
2018-09-12 13:33 ` [RFC PATCH 10/10] x86/fpu: defer FPU state load until return to userspace Sebastian Andrzej Siewior
2018-09-12 15:47 ` Andy Lutomirski
2018-09-19 17:05 ` Sebastian Andrzej Siewior
2018-09-21 3:45 ` Andy Lutomirski
2018-09-21 4:15 ` Andy Lutomirski
2018-09-26 11:12 ` Sebastian Andrzej Siewior
2018-09-26 14:34 ` Andy Lutomirski
2018-09-26 15:32 ` Sebastian Andrzej Siewior
2018-09-26 16:24 ` Andy Lutomirski
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