From: "Tian, Kevin" <kevin.tian@intel.com>
To: Jan Beulich <JBeulich@suse.com>,
Andrew Cooper <andrew.cooper3@citrix.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>,
"Nakajima, Jun" <jun.nakajima@intel.com>
Subject: Re: [PATCH 2/3] VMX: allocate VMCS pages from domain heap
Date: Wed, 21 Oct 2015 03:16:25 +0000 [thread overview]
Message-ID: <AADFC41AFE54684AB9EE6CBC0274A5D15F6D8EEF@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <5626351602000078000ACB2D@prv-mh.provo.novell.com>
> From: Jan Beulich [mailto:JBeulich@suse.com]
> Sent: Tuesday, October 20, 2015 6:36 PM
>
> >>> On 20.10.15 at 12:12, <andrew.cooper3@citrix.com> wrote:
> > On 19/10/15 16:22, Jan Beulich wrote:
> >> -static struct vmcs_struct *vmx_alloc_vmcs(void)
> >> +static paddr_t vmx_alloc_vmcs(void)
> >> {
> >> + struct page_info *pg;
> >> struct vmcs_struct *vmcs;
> >>
> >> - if ( (vmcs = alloc_xenheap_page()) == NULL )
> >> + if ( (pg = alloc_domheap_page(NULL, 0)) == NULL )
> >
> > As an observation, it would be good to pass v from the caller, and NUMA
> > allocate against v->domain here.
>
> Yes, in another patch.
which 'another patch'? suppose not PATCH 3/3 since I didn't' see
related change there.
>
> >> @@ -580,7 +583,7 @@ int vmx_cpu_up_prepare(unsigned int cpu)
> >> void vmx_cpu_dead(unsigned int cpu)
> >> {
> >> vmx_free_vmcs(per_cpu(vmxon_region, cpu));
> >> - per_cpu(vmxon_region, cpu) = NULL;
> >> + per_cpu(vmxon_region, cpu) = 0;
> >
> > While this is currently safe (as pa 0 is not part of the available heap
> > allocation range), might it be worth introducing a named sentential? I
> > can forsee a DMLite nested Xen scenario where we definitely don't need
> > to treat the low 1MB magically.
>
> I guess there are more things to adjust if we ever cared to recover
> the few hundred kb below 1Mb. And then I don't see why nested
> Xen would matter here: One major main reason for reserving that
> space is that we want to put the trampoline there. Do you think
> DMlite would allow us to get away without? But even if so, this
> would again fall under what I've said in the first sentence.
>
Could you at least introduce a macro first? Regardless of how much
things to adjust, this way makes future change simple.
Thanks
Kevin
next prev parent reply other threads:[~2015-10-21 3:16 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-19 15:10 [PATCH 0/3] VMX: misc adjustments Jan Beulich
2015-10-19 15:21 ` [PATCH 1/3] VMX: re-order definitions Jan Beulich
2015-10-21 3:04 ` Tian, Kevin
2015-10-19 15:22 ` [PATCH 2/3] VMX: allocate VMCS pages from domain heap Jan Beulich
2015-10-20 10:12 ` Andrew Cooper
2015-10-20 10:35 ` Jan Beulich
2015-10-21 3:16 ` Tian, Kevin [this message]
2015-10-21 5:54 ` Jan Beulich
2015-11-23 14:28 ` Jan Beulich
2015-11-24 5:04 ` Tian, Kevin
2015-11-24 7:50 ` Jan Beulich
2015-11-24 10:55 ` Andrew Cooper
2015-11-24 10:59 ` Andrew Cooper
2015-11-24 11:04 ` Jan Beulich
2015-11-24 11:09 ` Andrew Cooper
2015-10-19 15:23 ` [PATCH 3/3] vVMX: use latched VMCS machine address Jan Beulich
2015-10-21 5:44 ` Tian, Kevin
2016-02-23 8:34 ` Li, Liang Z
2016-02-23 10:31 ` Jan Beulich
2016-02-23 10:48 ` Li, Liang Z
2016-02-24 7:04 ` Li, Liang Z
2016-02-24 10:32 ` Jan Beulich
2016-02-24 15:08 ` Li, Liang Z
2016-02-25 6:50 ` Li, Liang Z
2016-02-25 9:01 ` Jan Beulich
2016-02-25 9:42 ` Li, Liang Z
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