From: Paolo Bonzini <pbonzini@redhat.com>
To: Nadav Amit <namit@cs.technion.ac.il>, mtosatti@redhat.com, hpa@zytor.com
Cc: gleb@kernel.org, tglx@linutronix.de, mingo@redhat.com,
x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/5] KVM: x86: Fix wrong masking on relative jump/call
Date: Wed, 07 May 2014 17:59:39 +0200 [thread overview]
Message-ID: <536A586B.2060200@redhat.com> (raw)
In-Reply-To: <1399465972-4026-6-git-send-email-namit@cs.technion.ac.il>
Il 07/05/2014 14:32, Nadav Amit ha scritto:
> Relative jumps and calls do the masking according to the operand size, and not
> according to the address size as the KVM emulator does today. In 64-bit mode,
> the resulting RIP is always 64-bit. Otherwise it is masked according to the
> instruction operand-size. Note that when 16-bit address size is used, bits
> 63:32 are unmodified.
The SDM says "If the operand-size attribute is 16, the upper two bytes
of the EIP register are cleared, resulting in a maximum instruction
pointer size of 16 bits". I'm not sure whether that should also imply
that 63:32 are _not_ unmodified (because you do a 32-bit write not a
16-bit one), but in any case it looks like masked_increment is not the
right function.
Paolo
next prev parent reply other threads:[~2014-05-07 15:59 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-07 12:32 [PATCH 0/5] KVM: x86: Fix exit handler and emulation bugs Nadav Amit
2014-05-07 12:32 ` [PATCH 1/5] KVM: x86: Emulator does not calculate address correctly Nadav Amit
2014-05-07 13:57 ` Paolo Bonzini
2014-05-07 15:21 ` Nadav Amit
2014-05-07 12:32 ` [PATCH 2/5] KVM: vmx: handle_dr does not handle RSP correctly Nadav Amit
2014-05-07 12:32 ` [PATCH 3/5] KVM: x86: Mark bit 7 in long-mode PDPTE according to 1GB pages support Nadav Amit
2014-05-07 12:32 ` [PATCH 4/5] KVM: x86: Wrong register masking in 64-bit mode Nadav Amit
2014-05-07 14:50 ` Bandan Das
2014-05-07 15:24 ` Paolo Bonzini
2014-05-07 16:11 ` Nadav Amit
2014-05-07 15:52 ` Paolo Bonzini
2014-05-08 12:27 ` Nadav Amit
2014-05-07 12:32 ` [PATCH 5/5] KVM: x86: Fix wrong masking on relative jump/call Nadav Amit
2014-05-07 14:43 ` Bandan Das
2014-05-07 15:57 ` Nadav Amit
2014-05-07 15:59 ` Paolo Bonzini [this message]
2014-05-07 16:00 ` [PATCH 0/5] KVM: x86: Fix exit handler and emulation bugs Paolo Bonzini
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