From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: tglx@linutronix.de, mingo@kernel.org, bp@suse.de,
luto@kernel.org, x86@kernel.org
Cc: len.brown@intel.com, dave.hansen@intel.com, jing2.liu@intel.com,
ravi.v.shankar@intel.com, linux-kernel@vger.kernel.org,
chang.seok.bae@intel.com, kvm@vger.kernel.org
Subject: [RFC PATCH 10/22] x86/fpu/xstate: Update xstate save function for supporting dynamic user xstate
Date: Thu, 1 Oct 2020 13:39:01 -0700 [thread overview]
Message-ID: <20201001203913.9125-11-chang.seok.bae@intel.com> (raw)
In-Reply-To: <20201001203913.9125-1-chang.seok.bae@intel.com>
copy_xregs_to_kernel() used to save all user states in an invariably
sufficient buffer. When the dynamic user state is enabled, it becomes
conditional which state to be saved.
fpu->state_mask can indicate which state components are reserved to be
saved in XSAVE buffer. Use it as XSAVE's instruction mask to select states.
KVM saves xstate in guest_fpu and user_fpu. With the change, the KVM code
needs to ensure a valid fpu->state_mask before XSAVE.
No functional change until the kernel supports dynamic user states.
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Reviewed-by: Len Brown <len.brown@intel.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: kvm@vger.kernel.org
---
arch/x86/include/asm/fpu/internal.h | 3 +--
arch/x86/kernel/fpu/core.c | 2 +-
arch/x86/kvm/x86.c | 11 ++++++++---
3 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 2dfb3b6f58fc..3b03ead87a46 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -331,9 +331,8 @@ static inline void copy_kernel_to_xregs_booting(struct xregs_state *xstate)
/*
* Save processor xstate to xsave area.
*/
-static inline void copy_xregs_to_kernel(struct xregs_state *xstate)
+static inline void copy_xregs_to_kernel(struct xregs_state *xstate, u64 mask)
{
- u64 mask = xfeatures_mask_all;
u32 lmask = mask;
u32 hmask = mask >> 32;
int err;
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index dca4961fcc36..ece6428ba85b 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -99,7 +99,7 @@ int copy_fpregs_to_fpstate(struct fpu *fpu)
if (likely(use_xsave())) {
struct xregs_state *xsave = &xstate->xsave;
- copy_xregs_to_kernel(xsave);
+ copy_xregs_to_kernel(xsave, fpu->state_mask);
/*
* AVX512 state is tracked here because its use is
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ecec6418ccca..a8b5f507083c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8842,15 +8842,20 @@ static int complete_emulated_mmio(struct kvm_vcpu *vcpu)
static void kvm_save_current_fpu(struct fpu *fpu)
{
+ struct fpu *src_fpu = ¤t->thread.fpu;
+
/*
* If the target FPU state is not resident in the CPU registers, just
* memcpy() from current, else save CPU state directly to the target.
*/
- if (test_thread_flag(TIF_NEED_FPU_LOAD))
- memcpy(&fpu->state, ¤t->thread.fpu.state,
+ if (test_thread_flag(TIF_NEED_FPU_LOAD)) {
+ memcpy(&fpu->state, &src_fpu->state,
fpu_kernel_xstate_default_size);
- else
+ } else {
+ if (fpu->state_mask != src_fpu->state_mask)
+ fpu->state_mask = src_fpu->state_mask;
copy_fpregs_to_fpstate(fpu);
+ }
}
/* Swap (qemu) user FPU context for the guest FPU context. */
--
2.17.1
next prev parent reply other threads:[~2020-10-01 20:43 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-01 20:38 [RFC PATCH 00/22] x86: Support Intel Advanced Matrix Extensions Chang S. Bae
2020-10-01 20:38 ` [RFC PATCH 01/22] x86/fpu/xstate: Modify area init helper prototypes to access all the possible areas Chang S. Bae
2020-10-01 20:38 ` [RFC PATCH 02/22] x86/fpu/xstate: Modify xstate copy " Chang S. Bae
2020-10-01 20:38 ` [RFC PATCH 03/22] x86/fpu/xstate: Modify address finder " Chang S. Bae
2020-10-01 20:38 ` [RFC PATCH 04/22] x86/fpu/xstate: Modify save and restore helper " Chang S. Bae
2020-10-01 20:38 ` [RFC PATCH 05/22] x86/fpu/xstate: Introduce a new variable for dynamic user states Chang S. Bae
2020-10-01 20:38 ` [RFC PATCH 06/22] x86/fpu/xstate: Outline dynamic xstate area size in the task context Chang S. Bae
2020-10-01 20:38 ` [RFC PATCH 07/22] x86/fpu/xstate: Introduce helpers to manage an xstate area dynamically Chang S. Bae
2020-10-01 23:41 ` Andy Lutomirski
2020-10-13 22:00 ` Brown, Len
2020-10-01 20:38 ` [RFC PATCH 08/22] x86/fpu/xstate: Define the scope of the initial xstate data Chang S. Bae
2020-10-01 20:39 ` [RFC PATCH 09/22] x86/fpu/xstate: Introduce wrapper functions for organizing xstate area access Chang S. Bae
2020-10-01 20:39 ` Chang S. Bae [this message]
2020-10-01 20:39 ` [RFC PATCH 11/22] x86/fpu/xstate: Update xstate area address finder for supporting dynamic user xstate Chang S. Bae
2020-10-01 20:39 ` [RFC PATCH 12/22] x86/fpu/xstate: Update xstate context copy function for supporting dynamic area Chang S. Bae
2020-10-01 20:39 ` [RFC PATCH 13/22] x86/fpu/xstate: Expand dynamic user state area on first use Chang S. Bae
2020-10-01 23:39 ` Andy Lutomirski
2020-10-13 22:31 ` Brown, Len
2020-10-13 22:43 ` Dave Hansen
2020-10-14 1:11 ` Andy Lutomirski
2020-10-14 6:03 ` Dave Hansen
2020-10-14 16:10 ` Andy Lutomirski
2020-10-14 16:29 ` Dave Hansen
2020-11-03 21:32 ` Bae, Chang Seok
2020-11-03 21:41 ` Dave Hansen
2020-11-03 21:53 ` Bae, Chang Seok
2020-10-14 10:41 ` Peter Zijlstra
2020-10-14 1:47 ` Andy Lutomirski
2020-10-01 20:39 ` [RFC PATCH 14/22] x86/fpu/xstate: Inherit dynamic user state when used in the parent Chang S. Bae
2020-10-01 20:39 ` [RFC PATCH 15/22] x86/fpu/xstate: Support ptracer-induced xstate area expansion Chang S. Bae
2020-10-01 20:39 ` [RFC PATCH 16/22] x86/fpu/xstate: Support dynamic user state in the signal handling path Chang S. Bae
2020-10-01 20:39 ` [RFC PATCH 17/22] x86/fpu/xstate: Extend the table for mapping xstate components with features Chang S. Bae
2020-10-01 20:39 ` [RFC PATCH 18/22] x86/cpufeatures/amx: Enumerate Advanced Matrix Extension (AMX) feature bits Chang S. Bae
2020-10-01 20:39 ` [RFC PATCH 19/22] x86/fpu/amx: Define AMX state components and have it used for boot-time checks Chang S. Bae
2020-10-01 20:39 ` [RFC PATCH 20/22] x86/fpu/amx: Enable the AMX feature in 64-bit mode Chang S. Bae
2020-10-01 20:39 ` [RFC PATCH 21/22] selftest/x86/amx: Include test cases for the AMX state management Chang S. Bae
2020-10-01 20:39 ` [RFC PATCH 22/22] x86/fpu/xstate: Introduce boot-parameters for control some state component support Chang S. Bae
2020-10-02 2:09 ` Randy Dunlap
2020-10-13 23:00 ` Brown, Len
2020-10-02 17:15 ` Andy Lutomirski
2020-10-02 17:26 ` Dave Hansen
2020-10-13 23:38 ` Brown, Len
2020-10-02 17:25 ` Dave Hansen
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