2012-05-01 13:06:11

by Michael S. Tsirkin

Subject: [PATCH] kvm: update eax documentation in signature cpuid

---

Pls apply on top of kvm cpuid bit.

diff --git a/Documentation/virtual/kvm/cpuid.txt b/Documentation/virtual/kvm/cpuid.txt
index 8820685..c6e85d8 100644
--- a/Documentation/virtual/kvm/cpuid.txt
+++ b/Documentation/virtual/kvm/cpuid.txt
@@ -10,11 +10,15 @@ a guest.
KVM cpuid functions are:

function: KVM_CPUID_SIGNATURE (0x40000000)
-returns : eax = 0,
+returns : eax = 0x40000001,
ebx = 0x4b4d564b,
ecx = 0x564b4d56,
edx = 0x4d.
Note that this value in ebx, ecx and edx corresponds to the string "KVMKVMKVM".
+The value in eax corresponds to the maximim cpuid function present in this leaf,
+and will be updated if more functions are added in the future.
+Note also that old hosts set eax value to 0x0. This should
+be interpreted as if the value was 0x40000001.
This function queries the presence of KVM cpuid leafs.

2012-05-01 13:24:28

by Takuya Yoshikawa

Subject: Re: [PATCH] kvm: update eax documentation in signature cpuid

On Tue, 1 May 2012 16:06:11 +0300
"Michael S. Tsirkin" <[email protected]> wrote:

> Note that this value in ebx, ecx and edx corresponds to the string "KVMKVMKVM".
> +The value in eax corresponds to the maximim cpuid function present in this leaf,

maximum?

Takuya

> +and will be updated if more functions are added in the future.
> +Note also that old hosts set eax value to 0x0. This should
> +be interpreted as if the value was 0x40000001.
> This function queries the presence of KVM cpuid leafs.