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From: Julian Stecklina <jsteckli@os.inf.tu-dresden.de>
To: kvm@vger.kernel.org
Subject: KVM VMX: register state after reset violates spec
Date: Thu, 29 Nov 2012 15:07:38 +0100	[thread overview]
Message-ID: <87y5hkjydx.fsf@os.inf.tu-dresden.de> (raw)

Hello,

we have noticed that at least on 3.6.8 with VMX after a VCPU has been
reset via the INIT-SIPI-SIPI sequence its register state violates
Intel's specification.

Specifically for our case we see at the end of vmx_vcpu_reset the
following vcpu state:

regs_avail=ffefffff regs_dirty=00010010
EIP=00000000 EAX=000006e8 EBX=00000001 ECX=80000001 EDX=00000600
ESI=0000d238 EDI=00000000 EBP=00000000 ESP=00000000

although EAX, EBX, ECX, ESI, EDI, EBP, ESP should _all_ be zero. See
http://download.intel.com/products/processor/manual/253668.pdf section
9.1.1 (page 9-2).

Shouldn't vmx_vcpu_reset actively clear those registers? And from a
quick glance at the SVM code the problem might exist there, too.

A workaround is to use qemu-kvm with -kvm-no-irqchip.

Julian


             reply	other threads:[~2012-11-29 14:24 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-29 14:07 Julian Stecklina [this message]
2012-11-29 14:38 ` [PATCH] KVM VMX: Make register state after reset conform to specification Julian Stecklina
2012-11-29 14:55 ` Julian Stecklina
2012-12-02 13:38 ` KVM VMX: register state after reset violates spec Gleb Natapov
2012-12-03 12:05   ` Julian Stecklina
2012-12-03 13:46   ` [PATCH v2] KVM: x86: Make register state after reset conform to specification Julian Stecklina
2012-12-04  9:48     ` Gleb Natapov
2012-12-04 12:13       ` [PATCH v3] " Julian Stecklina
2012-12-05 10:50         ` Gleb Natapov
2012-12-05 12:00           ` [PATCH v4] " Julian Stecklina
2012-12-05 13:27             ` Gleb Natapov
2012-12-05 14:26               ` [PATCH v5] " Julian Stecklina
2012-12-05 16:02                 ` Gleb Natapov
2012-12-05 14:27               ` [PATCH v4] " Julian Stecklina
2012-12-03 13:49   ` KVM VMX: register state after reset violates spec Julian Stecklina

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