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From: Matteo Signorini <signorinimatteo@gmail.com>
To: kvm@vger.kernel.org
Subject: ms_sysenter_eip zero value
Date: Sun, 23 Jan 2011 12:25:48 +0100	[thread overview]
Message-ID: <AANLkTi=S_xGDvsqX95swMuyv4EODRbVRnxJiik7A+zv3@mail.gmail.com> (raw)

Hi,

I'm having some problems understanding the sysenter instruction.
As far as I know, in order to successfully call the sysenter instruction,
MSR_IA32_SYSENTER_CS and MSR_IA32_SYSENTER_EIP registers have to be
correctly set.

So I printed the value of such registers while the VM was running but
the output is 0 for both.

now:

1) I'm having this problem ONLY with the Intel CPU (vmx.c source code).
When I run the same code on an AMD CPU (svm.c source code)
MSR_IA32_SYSENTER_EIP and MSR_IA32_SYSENTER_CS contain nonzero values.

2) I am 100% sure the guest is not executing an int80 but a sysenter

so there is something here I can't understand...
please help me solving this problem.

thank you for enlightening me on this issue,
Matteo

             reply	other threads:[~2011-01-23 11:25 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-23 11:25 Matteo Signorini [this message]
2011-01-26 11:24 ` ms_sysenter_eip zero value Avi Kivity
2011-01-27 13:01   ` Matteo

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