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>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Sebastian Andrzej Siewior" <bigeasy@linutronix.de>
Subject: [PATCH 13/23] x86/fpu: Make get_xsave_field_ptr() and get_xsave_addr() use feature number instead of mask
Date: Wed, 7 Nov 2018 20:48:48 +0100 [thread overview]
Message-ID: <20181107194858.9380-14-bigeasy@linutronix.de> (raw)
In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de>
After changing the argument of __raw_xsave_addr() from a mask to number
Dave suggested to check if it makes sense to do the same for
get_xsave_addr(). As it turns out it does. Only get_xsave_addr() needs
the mask to check if the requested feature is part of what is
support/saved and then uses the number again. The shift operation is
cheaper compared to "find last bit set". Also, the feature number uses
less opcode space compared to the mask :)
Make get_xsave_addr() argument a xfeature number instead of mask and fix
up its callers.
As part of this use xfeature_nr and xfeature_mask consistently.
This results in changes to the kvm code as:
feature -> xfeature_mask
index -> xfeature_nr
Suggested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
arch/x86/include/asm/fpu/xstate.h | 4 ++--
arch/x86/kernel/fpu/xstate.c | 23 +++++++++++------------
arch/x86/kernel/traps.c | 2 +-
arch/x86/kvm/x86.c | 28 ++++++++++++++--------------
arch/x86/mm/mpx.c | 6 +++---
5 files changed, 31 insertions(+), 32 deletions(-)
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 48581988d78c7..fbe41f808e5d8 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -46,8 +46,8 @@ extern void __init update_regset_xstate_info(unsigned int size,
u64 xstate_mask);
void fpu__xstate_clear_all_cpu_caps(void);
-void *get_xsave_addr(struct xregs_state *xsave, int xstate);
-const void *get_xsave_field_ptr(int xstate_field);
+void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
+const void *get_xsave_field_ptr(int xfeature_nr);
int using_compacted_format(void);
int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);
int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 3dfe3627deaf6..375226055a413 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -832,15 +832,15 @@ static void *__raw_xsave_addr(struct xregs_state *xsave, int xfeature_nr)
*
* Inputs:
* xstate: the thread's storage area for all FPU data
- * xstate_feature: state which is defined in xsave.h (e.g.
- * XFEATURE_MASK_FP, XFEATURE_MASK_SSE, etc...)
+ * xfeature_nr: state which is defined in xsave.h (e.g. XFEATURE_FP,
+ * XFEATURE_SSE, etc...)
* Output:
* address of the state in the xsave area, or NULL if the
* field is not present in the xsave buffer.
*/
-void *get_xsave_addr(struct xregs_state *xsave, int xstate_feature)
+void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr)
{
- int xfeature_nr;
+ u64 xfeature_mask = 1ULL << xfeature_nr;
/*
* Do we even *have* xsave state?
*/
@@ -852,11 +852,11 @@ void *get_xsave_addr(struct xregs_state *xsave, int xstate_feature)
* have not enabled. Remember that pcntxt_mask is
* what we write to the XCR0 register.
*/
- WARN_ONCE(!(xfeatures_mask & xstate_feature),
+ WARN_ONCE(!(xfeatures_mask & xfeature_mask),
"get of unsupported state");
/*
* This assumes the last 'xsave*' instruction to
- * have requested that 'xstate_feature' be saved.
+ * have requested that 'xfeature_mask' be saved.
* If it did not, we might be seeing and old value
* of the field in the buffer.
*
@@ -865,10 +865,9 @@ void *get_xsave_addr(struct xregs_state *xsave, int xstate_feature)
* or because the "init optimization" caused it
* to not be saved.
*/
- if (!(xsave->header.xfeatures & xstate_feature))
+ if (!(xsave->header.xfeatures & xfeature_mask))
return NULL;
- xfeature_nr = fls64(xstate_feature) - 1;
return __raw_xsave_addr(xsave, xfeature_nr);
}
EXPORT_SYMBOL_GPL(get_xsave_addr);
@@ -884,13 +883,13 @@ EXPORT_SYMBOL_GPL(get_xsave_addr);
* Note that this only works on the current task.
*
* Inputs:
- * @xsave_state: state which is defined in xsave.h (e.g. XFEATURE_MASK_FP,
- * XFEATURE_MASK_SSE, etc...)
+ * @xfeature_nr: state which is defined in xsave.h (e.g. XFEATURE_FP,
+ * XFEATURE_SSE, etc...)
* Output:
* address of the state in the xsave area or NULL if the state
* is not present or is in its 'init state'.
*/
-const void *get_xsave_field_ptr(int xsave_state)
+const void *get_xsave_field_ptr(int xfeature_nr)
{
struct fpu *fpu = ¤t->thread.fpu;
@@ -900,7 +899,7 @@ const void *get_xsave_field_ptr(int xsave_state)
*/
fpu__save(fpu);
- return get_xsave_addr(&fpu->state.xsave, xsave_state);
+ return get_xsave_addr(&fpu->state.xsave, xfeature_nr);
}
#ifdef CONFIG_ARCH_HAS_PKEYS
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 9b7c4ca8f0a73..626853b2ac344 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -455,7 +455,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
* which is all zeros which indicates MPX was not
* responsible for the exception.
*/
- bndcsr = get_xsave_field_ptr(XFEATURE_MASK_BNDCSR);
+ bndcsr = get_xsave_field_ptr(XFEATURE_BNDCSR);
if (!bndcsr)
goto exit_trap;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5cd5647120f2b..75301b439b6e4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3650,15 +3650,15 @@ static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu)
*/
valid = xstate_bv & ~XFEATURE_MASK_FPSSE;
while (valid) {
- u64 feature = valid & -valid;
- int index = fls64(feature) - 1;
- void *src = get_xsave_addr(xsave, feature);
+ u64 xfeature_mask = valid & -valid;
+ int xfeature_nr = fls64(xfeature_mask) - 1;
+ void *src = get_xsave_addr(xsave, xfeature_nr);
if (src) {
u32 size, offset, ecx, edx;
- cpuid_count(XSTATE_CPUID, index,
+ cpuid_count(XSTATE_CPUID, xfeature_nr,
&size, &offset, &ecx, &edx);
- if (feature == XFEATURE_MASK_PKRU)
+ if (xfeature_nr == XFEATURE_PKRU)
memcpy(dest + offset, &vcpu->arch.pkru,
sizeof(vcpu->arch.pkru));
else
@@ -3666,7 +3666,7 @@ static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu)
}
- valid -= feature;
+ valid -= xfeature_mask;
}
}
@@ -3693,22 +3693,22 @@ static void load_xsave(struct kvm_vcpu *vcpu, u8 *src)
*/
valid = xstate_bv & ~XFEATURE_MASK_FPSSE;
while (valid) {
- u64 feature = valid & -valid;
- int index = fls64(feature) - 1;
- void *dest = get_xsave_addr(xsave, feature);
+ u64 xfeature_mask = valid & -valid;
+ int xfeature_nr = fls64(xfeature_mask) - 1;
+ void *dest = get_xsave_addr(xsave, xfeature_nr);
if (dest) {
u32 size, offset, ecx, edx;
- cpuid_count(XSTATE_CPUID, index,
+ cpuid_count(XSTATE_CPUID, xfeature_nr,
&size, &offset, &ecx, &edx);
- if (feature == XFEATURE_MASK_PKRU)
+ if (xfeature_nr == XFEATURE_PKRU)
memcpy(&vcpu->arch.pkru, src + offset,
sizeof(vcpu->arch.pkru));
else
memcpy(dest, src + offset, size);
}
- valid -= feature;
+ valid -= xfeature_mask;
}
}
@@ -8704,11 +8704,11 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
if (init_event)
kvm_put_guest_fpu(vcpu);
mpx_state_buffer = get_xsave_addr(&vcpu->arch.guest_fpu.state.xsave,
- XFEATURE_MASK_BNDREGS);
+ XFEATURE_BNDREGS);
if (mpx_state_buffer)
memset(mpx_state_buffer, 0, sizeof(struct mpx_bndreg_state));
mpx_state_buffer = get_xsave_addr(&vcpu->arch.guest_fpu.state.xsave,
- XFEATURE_MASK_BNDCSR);
+ XFEATURE_BNDCSR);
if (mpx_state_buffer)
memset(mpx_state_buffer, 0, sizeof(struct mpx_bndcsr));
if (init_event)
diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
index 2385538e80656..bcd55cc3050c2 100644
--- a/arch/x86/mm/mpx.c
+++ b/arch/x86/mm/mpx.c
@@ -142,7 +142,7 @@ int mpx_fault_info(struct mpx_fault_info *info, struct pt_regs *regs)
goto err_out;
}
/* get bndregs field from current task's xsave area */
- bndregs = get_xsave_field_ptr(XFEATURE_MASK_BNDREGS);
+ bndregs = get_xsave_field_ptr(XFEATURE_BNDREGS);
if (!bndregs) {
err = -EINVAL;
goto err_out;
@@ -190,7 +190,7 @@ static __user void *mpx_get_bounds_dir(void)
* The bounds directory pointer is stored in a register
* only accessible if we first do an xsave.
*/
- bndcsr = get_xsave_field_ptr(XFEATURE_MASK_BNDCSR);
+ bndcsr = get_xsave_field_ptr(XFEATURE_BNDCSR);
if (!bndcsr)
return MPX_INVALID_BOUNDS_DIR;
@@ -376,7 +376,7 @@ static int do_mpx_bt_fault(void)
const struct mpx_bndcsr *bndcsr;
struct mm_struct *mm = current->mm;
- bndcsr = get_xsave_field_ptr(XFEATURE_MASK_BNDCSR);
+ bndcsr = get_xsave_field_ptr(XFEATURE_BNDCSR);
if (!bndcsr)
return -EINVAL;
/*
--
2.19.1
next prev parent reply other threads:[~2018-11-07 19:49 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-07 19:48 [PATCH v4] x86: load FPU registers on return to userland Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 01/23] x86/fpu: Use ULL for shift in xfeature_uncompacted_offset() Sebastian Andrzej Siewior
2018-11-08 11:38 ` Borislav Petkov
2018-11-09 16:56 ` Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 02/23] x86/fpu: Remove fpu->initialized usage in __fpu__restore_sig() Sebastian Andrzej Siewior
2018-11-08 14:57 ` Borislav Petkov
2018-11-09 17:35 ` Sebastian Andrzej Siewior
2018-11-09 18:52 ` Borislav Petkov
2018-11-09 23:25 ` Sebastian Andrzej Siewior
2018-11-12 15:56 ` [PATCH] x86/fpu: Disable BH while while loading FPU registers " Sebastian Andrzej Siewior
2018-11-12 17:48 ` Dave Hansen
2018-11-19 11:41 ` Sebastian Andrzej Siewior
2018-11-19 15:04 ` Dave Hansen
2018-11-19 15:06 ` Sebastian Andrzej Siewior
2018-11-19 15:08 ` Dave Hansen
2018-11-19 15:19 ` Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 03/23] x86/fpu: Remove fpu__restore() Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 04/23] x86/entry/32: Remove asm/math_emu.h include Sebastian Andrzej Siewior
2018-11-08 18:45 ` Andy Lutomirski
2018-11-07 19:48 ` [PATCH 05/23] x86/fpu: Remove preempt_disable() in fpu__clear() Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 06/23] x86/fpu: Always init the `state' " Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 07/23] x86/fpu: Remove fpu->initialized usage in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 08/23] x86/fpu: Remove fpu->initialized Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 09/23] x86/fpu: Remove user_fpu_begin() Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 10/23] x86/entry: Remove _TIF_ALLWORK_MASK Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 11/23] x86/fpu: Add (__)make_fpregs_active helpers Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 12/23] x86/fpu: Make __raw_xsave_addr() use feature number instead of mask Sebastian Andrzej Siewior
2018-11-07 19:48 ` Sebastian Andrzej Siewior [this message]
2018-11-07 19:48 ` [PATCH 14/23] x86/pkeys: Make init_pkru_value static Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 15/23] x86/fpu: Only write PKRU if it is different from current Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 16/23] x86/pkeys: Don't check if PKRU is zero before writting it Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 17/23] x86/fpu: Eager switch PKRU state Sebastian Andrzej Siewior
2018-11-08 11:12 ` Paolo Bonzini
2018-11-19 18:17 ` Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 18/23] x86/entry: Add TIF_NEED_FPU_LOAD Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 19/23] x86/fpu: Always store the registers in copy_fpstate_to_sigframe() Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 20/23] x86/fpu: Prepare copy_fpstate_to_sigframe() for TIF_NEED_FPU_LOAD Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 21/23] x86/fpu: Update xstate's PKRU value on write_pkru() Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 22/23] x86/fpu: Don't restore the FPU state directly from userland in __fpu__restore_sig() Sebastian Andrzej Siewior
2018-11-08 18:25 ` Andy Lutomirski
2018-11-09 19:09 ` Sebastian Andrzej Siewior
2018-11-07 19:48 ` [PATCH 23/23] x86/fpu: Defer FPU state load until return to userspace Sebastian Andrzej Siewior
2018-11-08 8:33 ` Sebastian Andrzej Siewior
2018-11-12 3:02 ` [PATCH v4] x86: load FPU registers on return to userland Wanpeng Li
2018-11-12 3:26 ` Jason A. Donenfeld
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