From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xen.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Wei Liu <wei.liu2@citrix.com>,
Ian Jackson <Ian.Jackson@eu.citrix.com>,
Jan Beulich <jbeulich@suse.com>
Subject: [PATCH v4 26/26] tools/libxc: Calculate xstate cpuid leaf from guest information
Date: Wed, 23 Mar 2016 16:36:29 +0000 [thread overview]
Message-ID: <1458750989-28967-27-git-send-email-andrew.cooper3@citrix.com> (raw)
In-Reply-To: <1458750989-28967-1-git-send-email-andrew.cooper3@citrix.com>
It is unsafe to generate the guests xstate leaves from host information, as it
prevents the differences between hosts from being hidden.
In addition, some further improvements and corrections:
- don't discard the known flags in sub-leaves 2..63 ECX
- zap sub-leaves beyond 62
- zap all bits in leaf 1, EBX/ECX. No XSS features are currently supported.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
CC: Wei Liu <wei.liu2@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
v3:
* Reintroduce MPX adjustment (this series has been in development since
before the introduction of MPX upstream, and it got lost in a rebase)
v4:
* Fold further improvements from Jan
---
tools/libxc/xc_cpuid_x86.c | 71 +++++++++++++++++++++++++++++++++++++---------
1 file changed, 57 insertions(+), 14 deletions(-)
diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
index fc7e20a..cf1f6b7 100644
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -398,54 +398,97 @@ static void intel_xc_cpuid_policy(xc_interface *xch,
}
}
+/* XSTATE bits in XCR0. */
+#define X86_XCR0_X87 (1ULL << 0)
+#define X86_XCR0_SSE (1ULL << 1)
+#define X86_XCR0_AVX (1ULL << 2)
+#define X86_XCR0_BNDREG (1ULL << 3)
+#define X86_XCR0_BNDCSR (1ULL << 4)
+#define X86_XCR0_LWP (1ULL << 62)
+
+#define X86_XSS_MASK (0) /* No XSS states supported yet. */
+
+/* Per-component subleaf flags. */
+#define XSTATE_XSS (1ULL << 0)
+#define XSTATE_ALIGN64 (1ULL << 1)
+
/* Configure extended state enumeration leaves (0x0000000D for xsave) */
static void xc_cpuid_config_xsave(xc_interface *xch,
const struct cpuid_domain_info *info,
const unsigned int *input, unsigned int *regs)
{
- if ( info->xfeature_mask == 0 )
+ uint64_t guest_xfeature_mask;
+
+ if ( info->xfeature_mask == 0 ||
+ !test_bit(X86_FEATURE_XSAVE, info->featureset) )
{
regs[0] = regs[1] = regs[2] = regs[3] = 0;
return;
}
+ guest_xfeature_mask = X86_XCR0_SSE | X86_XCR0_X87;
+
+ if ( test_bit(X86_FEATURE_AVX, info->featureset) )
+ guest_xfeature_mask |= X86_XCR0_AVX;
+
+ if ( test_bit(X86_FEATURE_MPX, info->featureset) )
+ guest_xfeature_mask |= X86_XCR0_BNDREG | X86_XCR0_BNDCSR;
+
+ if ( test_bit(X86_FEATURE_LWP, info->featureset) )
+ guest_xfeature_mask |= X86_XCR0_LWP;
+
+ /*
+ * Clamp to host mask. Should be no-op, as guest_xfeature_mask should not
+ * be able to be calculated as larger than info->xfeature_mask.
+ *
+ * TODO - see about making this a harder error.
+ */
+ guest_xfeature_mask &= info->xfeature_mask;
+
switch ( input[1] )
{
- case 0:
+ case 0:
/* EAX: low 32bits of xfeature_enabled_mask */
- regs[0] = info->xfeature_mask & 0xFFFFFFFF;
+ regs[0] = guest_xfeature_mask;
/* EDX: high 32bits of xfeature_enabled_mask */
- regs[3] = (info->xfeature_mask >> 32) & 0xFFFFFFFF;
+ regs[3] = guest_xfeature_mask >> 32;
/* ECX: max size required by all HW features */
{
unsigned int _input[2] = {0xd, 0x0}, _regs[4];
regs[2] = 0;
- for ( _input[1] = 2; _input[1] < 64; _input[1]++ )
+ for ( _input[1] = 2; _input[1] <= 62; _input[1]++ )
{
cpuid(_input, _regs);
if ( (_regs[0] + _regs[1]) > regs[2] )
regs[2] = _regs[0] + _regs[1];
}
}
- /* EBX: max size required by enabled features.
- * This register contains a dynamic value, which varies when a guest
- * enables or disables XSTATE features (via xsetbv). The default size
- * after reset is 576. */
+ /* EBX: max size required by enabled features.
+ * This register contains a dynamic value, which varies when a guest
+ * enables or disables XSTATE features (via xsetbv). The default size
+ * after reset is 576. */
regs[1] = 512 + 64; /* FP/SSE + XSAVE.HEADER */
break;
+
case 1: /* leaf 1 */
regs[0] = info->featureset[featureword_of(X86_FEATURE_XSAVEOPT)];
- regs[2] &= info->xfeature_mask;
- regs[3] = 0;
+ regs[2] = guest_xfeature_mask & X86_XSS_MASK;
+ regs[3] = (guest_xfeature_mask >> 32) & X86_XSS_MASK;
break;
- case 2 ... 63: /* sub-leaves */
- if ( !(info->xfeature_mask & (1ULL << input[1])) )
+
+ case 2 ... 62: /* per-component sub-leaves */
+ if ( !(guest_xfeature_mask & (1ULL << input[1])) )
{
regs[0] = regs[1] = regs[2] = regs[3] = 0;
break;
}
/* Don't touch EAX, EBX. Also cleanup ECX and EDX */
- regs[2] = regs[3] = 0;
+ regs[2] &= XSTATE_XSS | XSTATE_ALIGN64;
+ regs[3] = 0;
+ break;
+
+ default:
+ regs[0] = regs[1] = regs[2] = regs[3] = 0;
break;
}
}
--
2.1.4
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next prev parent reply other threads:[~2016-03-23 16:36 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-23 16:36 [PATCH v4 00/26] x86: Improvements to cpuid handling for guests Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 01/26] xen/public: Export cpu featureset information in the public API Andrew Cooper
2016-03-24 14:08 ` Jan Beulich
2016-03-24 14:12 ` Andrew Cooper
2016-03-24 14:16 ` Jan Beulich
2016-03-23 16:36 ` [PATCH v4 02/26] xen/x86: Script to automatically process featureset information Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 03/26] xen/x86: Collect more cpuid feature leaves Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 04/26] xen/x86: Mask out unknown features from Xen's capabilities Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 05/26] xen/x86: Annotate special features Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 06/26] xen/x86: Annotate VM applicability in featureset Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 07/26] xen/x86: Calculate maximum host and guest featuresets Andrew Cooper
2016-03-29 8:57 ` Jan Beulich
2016-03-23 16:36 ` [PATCH v4 08/26] xen/x86: Generate deep dependencies of features Andrew Cooper
2016-03-24 16:16 ` Jan Beulich
2016-03-23 16:36 ` [PATCH v4 09/26] xen/x86: Clear dependent features when clearing a cpu cap Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 10/26] xen/x86: Improve disabling of features which have dependencies Andrew Cooper
2016-03-28 15:18 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 11/26] xen/x86: Improvements to in-hypervisor cpuid sanity checks Andrew Cooper
2016-03-24 15:38 ` Andrew Cooper
2016-03-24 16:47 ` Jan Beulich
2016-03-24 17:01 ` Andrew Cooper
2016-03-24 17:11 ` Jan Beulich
2016-03-24 17:12 ` Andrew Cooper
2016-03-28 15:29 ` Konrad Rzeszutek Wilk
2016-04-05 15:25 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 12/26] x86/cpu: Move set_cpumask() calls into c_early_init() Andrew Cooper
2016-03-28 15:55 ` Konrad Rzeszutek Wilk
2016-04-05 16:19 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 13/26] x86/cpu: Sysctl and common infrastructure for levelling context switching Andrew Cooper
2016-03-24 16:58 ` Jan Beulich
2016-03-28 16:12 ` Konrad Rzeszutek Wilk
2016-04-05 16:33 ` Andrew Cooper
2016-03-28 17:37 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 14/26] x86/cpu: Rework AMD masking MSR setup Andrew Cooper
2016-03-28 18:55 ` Konrad Rzeszutek Wilk
2016-04-05 16:44 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 15/26] x86/cpu: Rework Intel masking/faulting setup Andrew Cooper
2016-03-28 19:14 ` Konrad Rzeszutek Wilk
2016-04-05 16:45 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 16/26] x86/cpu: Context switch cpuid masks and faulting state in context_switch() Andrew Cooper
2016-03-28 19:27 ` Konrad Rzeszutek Wilk
2016-04-05 18:34 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 17/26] x86/pv: Provide custom cpumasks for PV domains Andrew Cooper
2016-03-28 19:40 ` Konrad Rzeszutek Wilk
2016-04-05 16:55 ` Andrew Cooper
2016-03-23 16:36 ` [PATCH v4 18/26] x86/domctl: Update PV domain cpumasks when setting cpuid policy Andrew Cooper
2016-03-24 17:04 ` Jan Beulich
2016-03-24 17:05 ` Andrew Cooper
2016-03-28 19:51 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 19/26] xen+tools: Export maximum host and guest cpu featuresets via SYSCTL Andrew Cooper
2016-03-28 19:59 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 20/26] tools/libxc: Modify bitmap operations to take void pointers Andrew Cooper
2016-03-28 20:05 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 21/26] tools/libxc: Use public/featureset.h for cpuid policy generation Andrew Cooper
2016-03-28 20:07 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 22/26] tools/libxc: Expose the automatically generated cpu featuremask information Andrew Cooper
2016-03-28 20:08 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 23/26] tools: Utility for dealing with featuresets Andrew Cooper
2016-03-28 20:26 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 24/26] tools/libxc: Wire a featureset through to cpuid policy logic Andrew Cooper
2016-03-28 20:39 ` Konrad Rzeszutek Wilk
2016-03-23 16:36 ` [PATCH v4 25/26] tools/libxc: Use featuresets rather than guesswork Andrew Cooper
2016-03-23 16:36 ` Andrew Cooper [this message]
2016-03-24 17:20 ` [PATCH v4 26/26] tools/libxc: Calculate xstate cpuid leaf from guest information Wei Liu
2016-03-31 7:48 ` Jan Beulich
2016-04-05 17:48 ` Andrew Cooper
2016-04-07 0:16 ` Jan Beulich
2016-04-07 0:40 ` Andrew Cooper
2016-04-07 0:56 ` Jan Beulich
2016-04-07 11:34 ` Andrew Cooper
2016-03-24 10:27 ` [PATCH v4 00/26] x86: Improvements to cpuid handling for guests Jan Beulich
2016-03-24 10:28 ` Andrew Cooper
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