From: Jan Beulich <jbeulich@suse.com>
To: "Durrant, Paul" <pdurrant@amazon.co.uk>
Cc: "Kevin Tian" <kevin.tian@intel.com>, "Wei Liu" <wl@xen.org>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Jun Nakajima" <jun.nakajima@intel.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH 2/3] x86 / hvm: add domain_relinquish_resources() method
Date: Wed, 22 Jan 2020 17:00:30 +0100 [thread overview]
Message-ID: <6e32eeac-29d8-6e1b-f7be-5e2df9d104e4@suse.com> (raw)
In-Reply-To: <9ad0b7eec02945dba00017f3bfe85730@EX13D32EUC003.ant.amazon.com>
On 22.01.2020 16:56, Durrant, Paul wrote:
>> -----Original Message-----
>> From: Jan Beulich <jbeulich@suse.com>
>> Sent: 22 January 2020 15:51
>> To: Durrant, Paul <pdurrant@amazon.co.uk>
>> Cc: xen-devel@lists.xenproject.org; Andrew Cooper
>> <andrew.cooper3@citrix.com>; Wei Liu <wl@xen.org>; Roger Pau Monné
>> <roger.pau@citrix.com>; Jun Nakajima <jun.nakajima@intel.com>; Kevin Tian
>> <kevin.tian@intel.com>
>> Subject: Re: [PATCH 2/3] x86 / hvm: add domain_relinquish_resources()
>> method
>>
>> On 21.01.2020 13:00, Paul Durrant wrote:
>>> There are two functions in hvm.c to deal with tear-down and a domain:
>>> hvm_domain_relinquish_resources() and hvm_domain_destroy(). However,
>> only
>>> the latter has an associated method in 'hvm_funcs'. This patch adds
>>> a method for the former and stub definitions for SVM and VMX.
>>
>> Why the stubs? Simply ...
>>
>>> --- a/xen/arch/x86/hvm/hvm.c
>>> +++ b/xen/arch/x86/hvm/hvm.c
>>> @@ -715,6 +715,8 @@ int hvm_domain_initialise(struct domain *d)
>>>
>>> void hvm_domain_relinquish_resources(struct domain *d)
>>> {
>>> + hvm_funcs.domain_relinquish_resources(d);
>>
>> ... stick a NULL check around this one. I also wonder whether, it
>> being entirely new, this wouldn't better use alternative call
>> patching right from the beginning. It's not the hottest path, but
>> avoiding indirect calls seems quite desirable, especially when
>> doing so is relatively cheap.
>>
>
> I'd like it to align with the rest of the hvm_funcs so I'll add the
> NULL check, but alternatives patch for all hvm_funcs seems like a
> good thing I the longer term.
The frequently used ones have been converted already. Hence my
suggestion to make new ones use that model from the beginning.
Jan
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next prev parent reply other threads:[~2020-01-22 16:00 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-21 12:00 [Xen-devel] [PATCH 0/3] purge free_shared_domheap_page() Paul Durrant
2020-01-21 12:00 ` [Xen-devel] [PATCH 1/3] x86 / vmx: make apic_access_mfn type-safe Paul Durrant
2020-01-22 2:51 ` Tian, Kevin
2020-01-22 14:05 ` Andrew Cooper
2020-01-22 15:48 ` Jan Beulich
2020-01-21 12:00 ` [Xen-devel] [PATCH 2/3] x86 / hvm: add domain_relinquish_resources() method Paul Durrant
2020-01-22 15:50 ` Jan Beulich
2020-01-22 15:56 ` Durrant, Paul
2020-01-22 16:00 ` Jan Beulich [this message]
2020-01-22 16:02 ` Durrant, Paul
2020-01-21 12:00 ` [Xen-devel] [PATCH 3/3] x86 / vmx: use a 'normal' domheap page for APIC_DEFAULT_PHYS_BASE Paul Durrant
2020-01-21 12:29 ` Julien Grall
2020-01-21 12:37 ` Durrant, Paul
2020-01-22 3:19 ` Tian, Kevin
2020-01-22 11:25 ` Durrant, Paul
2020-01-22 16:17 ` Jan Beulich
2020-01-22 16:27 ` Durrant, Paul
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