From: Jan Kiszka <jan.kiszka@web.de>
To: Paolo Bonzini <pbonzini@redhat.com>, kvm <kvm@vger.kernel.org>
Cc: Joerg Roedel <joro@8bytes.org>,
Valentine Sinitsyn <valentine.sinitsyn@gmail.com>
Subject: nSVM: interception checks on emulation (was: [PATCH] KVM: nSVM: Fix IOIO size reported on emulation)
Date: Mon, 30 Jun 2014 11:27:48 +0200 [thread overview]
Message-ID: <53B12D94.2060900@web.de> (raw)
In-Reply-To: <53B128B9.1030205@web.de>
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On 2014-06-30 11:07, Jan Kiszka wrote:
> I'm seeing one more issue now: on emulation of "in (%dx),%eax", we leave
> to user space several times and check interception also several times
Correction: we only leave once for user space.
> after returning. We use dx to calculate the port number for the
> interception check. But at some point, user space (QEMU) decides to
> update that register during vmport access - and now we check the wrong
> port in the bitmap (namely port 0). Ideas?
>
> In general, the same interception checks are done multiple times. Once
> after the exit, then again during emulation. Can't we avoid this somehow?
>
OK, we have different interception stages, but it seems we take multiple
ones when we should only take a single:
qemu-system-x86-4455 [000] 38083.617545: kvm_exit: reason EXIT_IOIO rip 0x7fc6ead774e4 info 56580241 7fc6ead774e5
qemu-system-x86-4455 [000] 38083.617547: kvm_nested_vmexit: rip 7fc6ead774e4 reason EXIT_IOIO info1 56580241 info2 7fc6ead774e5 int_info 0 int_info_err 0
qemu-system-x86-4455 [000] 38083.617548: bprint: nested_svm_intercept: 5658 4 3c00bacb 0 1 f
qemu-system-x86-4455 [000] 38083.617549: bprint: nested_svm_intercept: f0
qemu-system-x86-4455 [000] 38083.617553: kvm_emulate_insn: 0:7fc6ead774e4: ed
qemu-system-x86-4455 [000] 38083.617555: bprint: svm_check_intercept: 5658 2 4 43
qemu-system-x86-4455 [000] 38083.617556: bprint: nested_svm_intercept: 5658 4 3c00bacb 0 1 f
qemu-system-x86-4455 [000] 38083.617556: bprint: nested_svm_intercept: f0
qemu-system-x86-4455 [000] 38083.617559: kvm_userspace_exit: reason KVM_EXIT_IO (2)
qemu-system-x86-4455 [000] 38083.617567: bprint: kvm_arch_vcpu_ioctl_get_regs: 5658
qemu-system-x86-4455 [000] 38083.617598: bprint: kvm_arch_vcpu_ioctl_set_regs: 0
qemu-system-x86-4455 [000] 38083.617628: bprint: svm_check_intercept: 0 2 4 43
qemu-system-x86-4455 [000] 38083.617629: bprint: nested_svm_intercept: 0 4 3c00b000 0 1 f
qemu-system-x86-4455 [000] 38083.617630: bprint: nested_svm_intercept: ff
qemu-system-x86-4455 [000] 38083.617631: kvm_nested_vmexit_inject: reason EXIT_IOIO info1 241 info2 7fc6ead774e4 int_info 0 int_info_err 0
And you can also see the rdx writing of user space here (rdx is printed
in kvm_arch_vcpu_ioctl_*).
Jan
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next prev parent reply other threads:[~2014-06-30 9:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-30 9:07 [PATCH] KVM: nSVM: Fix IOIO size reported on emulation Jan Kiszka
2014-06-30 9:27 ` Jan Kiszka [this message]
2014-06-30 10:52 ` [PATCH] KVM: nSVM: Set correct port for IOIO interception evaluation Jan Kiszka
2014-07-01 15:37 ` Joerg Roedel
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