From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xenproject.org>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
"Jan Beulich" <JBeulich@suse.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: [PATCH v2 3/4] x86/cpu-policy: Simplify recalculate_xstate()
Date: Mon, 29 Apr 2024 19:28:22 +0100 [thread overview]
Message-ID: <20240429182823.1130436-4-andrew.cooper3@citrix.com> (raw)
In-Reply-To: <20240429182823.1130436-1-andrew.cooper3@citrix.com>
Make use of the new xstate_uncompressed_size() helper rather than maintaining
the running calculation while accumulating feature components.
The rest of the CPUID data can come direct from the raw cpu policy. All
per-component data form an ABI through the behaviour of the X{SAVE,RSTOR}*
instructions.
Use for_each_set_bit() rather than opencoding a slightly awkward version of
it. Mask the attributes in ecx down based on the visible features. This
isn't actually necessary for any components or attributes defined at the time
of writing (up to AMX), but is added out of an abundance of caution.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
v2:
* Tie ALIGN64 to xsavec rather than xsaves.
---
xen/arch/x86/cpu-policy.c | 55 +++++++++++--------------------
xen/arch/x86/include/asm/xstate.h | 1 +
2 files changed, 21 insertions(+), 35 deletions(-)
diff --git a/xen/arch/x86/cpu-policy.c b/xen/arch/x86/cpu-policy.c
index 4b6d96276399..fc7933be8577 100644
--- a/xen/arch/x86/cpu-policy.c
+++ b/xen/arch/x86/cpu-policy.c
@@ -193,8 +193,7 @@ static void sanitise_featureset(uint32_t *fs)
static void recalculate_xstate(struct cpu_policy *p)
{
uint64_t xstates = XSTATE_FP_SSE;
- uint32_t xstate_size = XSTATE_AREA_MIN_SIZE;
- unsigned int i, Da1 = p->xstate.Da1;
+ unsigned int i, ecx_mask = 0, Da1 = p->xstate.Da1;
/*
* The Da1 leaf is the only piece of information preserved in the common
@@ -206,61 +205,47 @@ static void recalculate_xstate(struct cpu_policy *p)
return;
if ( p->basic.avx )
- {
xstates |= X86_XCR0_YMM;
- xstate_size = max(xstate_size,
- xstate_offsets[X86_XCR0_YMM_POS] +
- xstate_sizes[X86_XCR0_YMM_POS]);
- }
if ( p->feat.mpx )
- {
xstates |= X86_XCR0_BNDREGS | X86_XCR0_BNDCSR;
- xstate_size = max(xstate_size,
- xstate_offsets[X86_XCR0_BNDCSR_POS] +
- xstate_sizes[X86_XCR0_BNDCSR_POS]);
- }
if ( p->feat.avx512f )
- {
xstates |= X86_XCR0_OPMASK | X86_XCR0_ZMM | X86_XCR0_HI_ZMM;
- xstate_size = max(xstate_size,
- xstate_offsets[X86_XCR0_HI_ZMM_POS] +
- xstate_sizes[X86_XCR0_HI_ZMM_POS]);
- }
if ( p->feat.pku )
- {
xstates |= X86_XCR0_PKRU;
- xstate_size = max(xstate_size,
- xstate_offsets[X86_XCR0_PKRU_POS] +
- xstate_sizes[X86_XCR0_PKRU_POS]);
- }
- p->xstate.max_size = xstate_size;
+ /* Subleaf 0 */
+ p->xstate.max_size =
+ xstate_uncompressed_size(xstates & ~XSTATE_XSAVES_ONLY);
p->xstate.xcr0_low = xstates & ~XSTATE_XSAVES_ONLY;
p->xstate.xcr0_high = (xstates & ~XSTATE_XSAVES_ONLY) >> 32;
+ /* Subleaf 1 */
p->xstate.Da1 = Da1;
+ if ( p->xstate.xsavec )
+ ecx_mask |= XSTATE_ALIGN64;
+
if ( p->xstate.xsaves )
{
+ ecx_mask |= XSTATE_XSS;
p->xstate.xss_low = xstates & XSTATE_XSAVES_ONLY;
p->xstate.xss_high = (xstates & XSTATE_XSAVES_ONLY) >> 32;
}
- else
- xstates &= ~XSTATE_XSAVES_ONLY;
- for ( i = 2; i < min(63UL, ARRAY_SIZE(p->xstate.comp)); ++i )
+ /* Subleafs 2+ */
+ xstates &= ~XSTATE_FP_SSE;
+ BUILD_BUG_ON(ARRAY_SIZE(p->xstate.comp) < 63);
+ for_each_set_bit ( i, &xstates, 63 )
{
- uint64_t curr_xstate = 1UL << i;
-
- if ( !(xstates & curr_xstate) )
- continue;
-
- p->xstate.comp[i].size = xstate_sizes[i];
- p->xstate.comp[i].offset = xstate_offsets[i];
- p->xstate.comp[i].xss = curr_xstate & XSTATE_XSAVES_ONLY;
- p->xstate.comp[i].align = curr_xstate & xstate_align;
+ /*
+ * Pass through size (eax) and offset (ebx) directly. Visbility of
+ * attributes in ecx limited by visible features in Da1.
+ */
+ p->xstate.raw[i].a = raw_cpu_policy.xstate.raw[i].a;
+ p->xstate.raw[i].b = raw_cpu_policy.xstate.raw[i].b;
+ p->xstate.raw[i].c = raw_cpu_policy.xstate.raw[i].c & ecx_mask;
}
}
diff --git a/xen/arch/x86/include/asm/xstate.h b/xen/arch/x86/include/asm/xstate.h
index f5115199d4f9..bfb66dd766b6 100644
--- a/xen/arch/x86/include/asm/xstate.h
+++ b/xen/arch/x86/include/asm/xstate.h
@@ -40,6 +40,7 @@ extern uint32_t mxcsr_mask;
#define XSTATE_XSAVES_ONLY 0
#define XSTATE_COMPACTION_ENABLED (1ULL << 63)
+#define XSTATE_XSS (1U << 0)
#define XSTATE_ALIGN64 (1U << 1)
extern u64 xfeature_mask;
--
2.30.2
next prev parent reply other threads:[~2024-04-29 18:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-29 18:28 [PATCH v2 0/4] x86/xstate: Fixes to size calculations Andrew Cooper
2024-04-29 18:28 ` [PATCH v2 1/4] x86/hvm: Defer the size calculation in hvm_save_cpu_xsave_states() Andrew Cooper
2024-05-02 12:08 ` Jan Beulich
2024-04-29 18:28 ` [PATCH v2 2/4] x86/xstate: Rework xstate_ctxt_size() as xstate_uncompressed_size() Andrew Cooper
2024-05-02 12:19 ` Jan Beulich
2024-05-02 13:17 ` Andrew Cooper
2024-04-29 18:28 ` Andrew Cooper [this message]
2024-05-02 12:39 ` [PATCH v2 3/4] x86/cpu-policy: Simplify recalculate_xstate() Jan Beulich
2024-05-02 13:24 ` Andrew Cooper
2024-05-02 14:33 ` Jan Beulich
2024-04-29 18:28 ` [PATCH v2 4/4] x86/cpuid: Fix handling of xsave dynamic leaves Andrew Cooper
2024-05-02 13:04 ` Jan Beulich
2024-05-02 14:32 ` Andrew Cooper
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