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From: "Daniel P. Smith" <dpsmith@apertussolutions.com>
To: Jan Beulich <jbeulich@suse.com>, Henry Wang <xin.wang2@amd.com>
Cc: Anthony PERARD <anthony.perard@citrix.com>,
	Juergen Gross <jgross@suse.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	George Dunlap <george.dunlap@citrix.com>,
	Julien Grall <julien@xen.org>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Bertrand Marquis <bertrand.marquis@arm.com>,
	Michal Orzel <michal.orzel@amd.com>,
	Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
	Alec Kwapis <alec.kwapis@medtronic.com>,
	xen-devel@lists.xenproject.org
Subject: Re: [PATCH 2/3] xen/arm, tools: Add a new HVM_PARAM_MAGIC_BASE_PFN key in HVMOP
Date: Mon, 29 Apr 2024 20:31:04 -0400	[thread overview]
Message-ID: <ce942d72-f214-4043-bf61-9d124c0bca64@apertussolutions.com> (raw)
In-Reply-To: <3af4f1c7-9059-436b-9449-94bd7aad9eed@suse.com>


On 4/26/24 02:21, Jan Beulich wrote:
> On 26.04.2024 05:14, Henry Wang wrote:
>> --- a/xen/include/public/hvm/params.h
>> +++ b/xen/include/public/hvm/params.h
>> @@ -76,6 +76,7 @@
>>    */
>>   #define HVM_PARAM_STORE_PFN    1
>>   #define HVM_PARAM_STORE_EVTCHN 2
>> +#define HVM_PARAM_MAGIC_BASE_PFN    3
>>   
>>   #define HVM_PARAM_IOREQ_PFN    5
> 
> Considering all adjacent values are used, it is overwhelmingly likely that
> 3 was once used, too. Such re-use needs to be done carefully. Since you
> need this for Arm only, that's likely okay, but doesn't go without (a)
> saying and (b) considering the possible future case of dom0less becoming
> arch-agnostic, or hyperlaunch wanting to extend the scope. Plus (c) imo
> this also needs at least a comment, maybe even an #ifdef, seeing how x86-
> focused most of the rest of this header is.

I would recommend having two new params,

#define HVM_PARAM_HV_RSRV_BASE_PVH 3
#define HVM_PARAM_HV_RSRV_SIZE 4

This will communicate how many pages have been reserved and where those 
pages are located.

v/r,
dps


  parent reply	other threads:[~2024-04-30  0:31 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-26  3:14 [PATCH 0/3] Guest magic region allocation for 11 Dom0less domUs - Take two Henry Wang
2024-04-26  3:14 ` [PATCH 1/3] xen/arm/dom0less-build: Alloc magic pages for Dom0less DomUs from hypervisor Henry Wang
2024-04-30  0:27   ` Daniel P. Smith
2024-04-30  2:55     ` Henry Wang
2024-04-30 10:22       ` Daniel P. Smith
2024-05-06  3:13         ` Henry Wang
2024-05-10  7:37   ` Michal Orzel
2024-05-10  7:42     ` Henry Wang
2024-04-26  3:14 ` [PATCH 2/3] xen/arm, tools: Add a new HVM_PARAM_MAGIC_BASE_PFN key in HVMOP Henry Wang
2024-04-26  6:21   ` Jan Beulich
2024-04-26  6:30     ` Henry Wang
2024-04-26  6:50       ` Jan Beulich
2024-04-26  7:02         ` Henry Wang
2024-04-30  0:31     ` Daniel P. Smith [this message]
2024-04-30  2:51       ` Henry Wang
2024-04-30  6:11         ` Jan Beulich
2024-04-30  8:12           ` Henry Wang
2024-04-30  8:51             ` Jan Beulich
2024-04-30  0:35   ` Daniel P. Smith
2024-04-30  1:25     ` Daniel P. Smith
2024-05-02 18:08   ` Stefano Stabellini
2024-05-06  2:01     ` Henry Wang
2024-04-26  3:14 ` [PATCH 3/3] tools/init-dom0less: Avoid hardcoding GUEST_MAGIC_BASE Henry Wang

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