From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>,
sstabellini@kernel.org, wei.liu2@citrix.com,
George.Dunlap@eu.citrix.com, andrew.cooper3@citrix.com,
ian.jackson@eu.citrix.com, tim@xen.org, julien.grall@arm.com,
jbeulich@suse.com
Subject: [PATCH v11 3/3] xen: add some comments in include/public/arch-x86/cpuid.h
Date: Thu, 28 Sep 2017 12:02:26 +0200 [thread overview]
Message-ID: <20170928100226.15280-4-jgross@suse.com> (raw)
In-Reply-To: <20170928100226.15280-1-jgross@suse.com>
Leaf 4 of the Xen-specific CPUID leaves isn't mentioned at all in
include/public/arch-x86/cpuid.h, the comments for leaf 5 don't tell
anything about the sub-leaf semantics.
Add comments to clarify the interface.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
---
xen/include/public/arch-x86/cpuid.h | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/xen/include/public/arch-x86/cpuid.h b/xen/include/public/arch-x86/cpuid.h
index 3d88c15598..f7569d58b0 100644
--- a/xen/include/public/arch-x86/cpuid.h
+++ b/xen/include/public/arch-x86/cpuid.h
@@ -74,10 +74,26 @@
#define XEN_CPUID_FEAT1_MMU_PT_UPDATE_PRESERVE_AD (1u<<0)
/*
+ * Leaf 4 (0x40000x03)
+ * Sub-leaf 0: EAX: bit 0: emulated tsc
+ * bit 1: host tsc is known to be reliable
+ * bit 2: RDTSCP instruction available
+ * EBX: tsc_mode: 0=default (emulate if necessary), 1=emulate,
+ * 2=no emulation, 3=no emulation + TSC_AUX support
+ * ECX: guest tsc frequency in kHz
+ * EDX: guest tsc incarnation (migration count)
+ * Sub-leaf 1: EAX: tsc offset low part
+ * EBX: tsc offset high part
+ * ECX: multiplicator for tsc->ns conversion
+ * EDX: shift amount for tsc->ns conversion
+ * Sub-leaf 2: EAX: host tsc frequency in kHz
+ */
+
+/*
* Leaf 5 (0x40000x04)
* HVM-specific features
- * EAX: Features
- * EBX: vcpu id (iff EAX has XEN_HVM_CPUID_VCPU_ID_PRESENT flag)
+ * Sub-leaf 0: EAX: Features
+ * Sub-leaf 0: EBX: vcpu id (iff EAX has XEN_HVM_CPUID_VCPU_ID_PRESENT flag)
*/
#define XEN_HVM_CPUID_APIC_ACCESS_VIRT (1u << 0) /* Virtualized APIC registers */
#define XEN_HVM_CPUID_X2APIC_VIRT (1u << 1) /* Virtualized x2APIC accesses */
--
2.12.3
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next prev parent reply other threads:[~2017-09-28 10:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-28 10:02 [PATCH v11 0/3] xen: better grant v2 support Juergen Gross
2017-09-28 10:02 ` [PATCH v11 1/3] xen: make grant resource limits per domain Juergen Gross
2017-10-03 13:33 ` Julien Grall
2017-09-28 10:02 ` [PATCH v11 2/3] xen: add new Xen cpuid node for max address width info Juergen Gross
2017-09-28 10:02 ` Juergen Gross [this message]
2017-09-28 19:02 ` [PATCH v11 0/3] xen: better grant v2 support Andrew Cooper
2017-09-29 4:33 ` Juergen Gross
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