From: "Jan Beulich" <JBeulich@suse.com>
To: Kevin.Mayer@gdata.de
Cc: andrew.cooper3@citrix.com, xen-devel@lists.xen.org
Subject: Re: Xen 4.6.1 crash with altp2m enabledbydefault
Date: Mon, 08 Aug 2016 04:29:17 -0600 [thread overview]
Message-ID: <57A87B1D0200007800103B6D@prv-mh.provo.novell.com> (raw)
In-Reply-To: <5C9C3B9BEF1B354596EAE3D6800D876B2D3222F6@e2.gdata.de>
>>> On 08.08.16 at 11:48, <Kevin.Mayer@gdata.de> wrote:
> vmx_vmenter_helper is not part of the call stack. The address is simply the
> location of the ud2 to which the
> __vmwrite(HOST_CR0, v->arch.hvm_vmx.host_cr0);
> In
> static void vmx_fpu_leave(struct vcpu *v)
> jumps.
> There are two vmwrites in vmx_vcpu_update_eptp (called by
> altp2m_vcpu_destroy):
> __vmwrite(EPT_POINTER, ept_get_eptp(ept));
> __vmwrite(EPTP_INDEX, vcpu_altp2m(v).p2midx);
>
> And four in vmx_vcpu_update_vmfunc_ve (also called by altp2m_vcpu_destroy)
> __vmwrite(VM_FUNCTION_CONTROL, VMX_VMFUNC_EPTP_SWITCHING);
> __vmwrite(EPTP_LIST_ADDR, virt_to_maddr(d->arch.altp2m_eptp));
> __vmwrite(VIRT_EXCEPTION_INFO, mfn_x(mfn) << PAGE_SHIFT);
> __vmwrite(SECONDARY_VM_EXEC_CONTROL,
> v->arch.hvm_vmx.secondary_exec_control);
>
> After the altp2m-part hvm_vcpu_destroy also calls nestedhvm_vcpu_destroy(v),
> but this code path is executed unconditionally so I assume that the error
> lies somewhere in the altp2m_vcpu_destroy(v).
>
> What exactly are the vmx_vmcs_enter / exit required for? I often see the
> vmx_vmcs_enter; __vmwrite; vmx_vmcs_exit combination. Need the __vmwrites be
> guarded by an enter / exit ( which Is not the case in the static void
> vmx_fpu_leave(struct vcpu *v) )?
On code paths where the correct VMCS may not be the current one
it is necessary to frame vmread / vmwrite accordingly.
> Is it possible that the
> altp2m_vcpu_destroy->vmx_vcpu_update_eptp->vmx_vmcs_exit->vmx_clear_vmcs
> invalidates the vmcs for the current vcpu?
I certainly can't exclude this possibility.
Jan
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next prev parent reply other threads:[~2016-08-08 10:29 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-29 7:33 Xen 4.6.1 crash with altp2m enabled by default Kevin.Mayer
2016-07-29 9:57 ` Dario Faggioli
2016-07-29 10:05 ` Andrew Cooper
2016-08-02 11:45 ` Kevin.Mayer
2016-08-02 12:34 ` Jan Beulich
2016-08-03 13:24 ` Kevin.Mayer
2016-08-03 13:54 ` Jan Beulich
2016-08-04 15:08 ` Kevin.Mayer
2016-08-04 15:35 ` Jan Beulich
2016-08-05 12:51 ` Xen 4.6.1 crash with altp2m enabled bydefault Kevin.Mayer
2016-08-05 14:48 ` Jan Beulich
2016-08-08 9:48 ` Xen 4.6.1 crash with altp2m enabledbydefault Kevin.Mayer
2016-08-08 10:29 ` Jan Beulich [this message]
2016-08-19 10:01 ` Kevin.Mayer
2016-08-22 11:58 ` Andrew Cooper
2016-08-22 12:22 ` Kevin.Mayer
2016-09-07 8:35 ` Kevin.Mayer
2016-09-21 14:18 ` Kevin.Mayer
2016-09-22 10:13 ` Jan Beulich
[not found] ` <5C9C3B9BEF1B354596EAE3D6800D876B2DCF7138@e3.gdata.de>
[not found] ` <57E405970200007800111B26@prv-mh.provo.novell.com>
[not found] ` <5C9C3B9BEF1B354596EAE3D6800D876B2DCF7254@e3.gdata.de>
2016-09-26 9:20 ` Xen 4.6.1 crash with altp2menabledbydefault Jan Beulich
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