From: Henry Wang <xin.wang2@amd.com>
To: Michal Orzel <michal.orzel@amd.com>, <xen-devel@lists.xenproject.org>
Cc: Anthony PERARD <anthony.perard@citrix.com>,
Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Julien Grall <julien@xen.org>,
Bertrand Marquis <bertrand.marquis@arm.com>,
"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
Alec Kwapis <alec.kwapis@medtronic.com>,
"Daniel P . Smith" <dpsmith@apertussolutions.com>
Subject: Re: [PATCH 1/3] xen/arm/dom0less-build: Alloc magic pages for Dom0less DomUs from hypervisor
Date: Fri, 10 May 2024 15:42:32 +0800 [thread overview]
Message-ID: <d357beeb-6874-4262-8137-8b4145fd64c4@amd.com> (raw)
In-Reply-To: <5d3ead96-5079-4fa3-b5fd-4d9803c251b6@amd.com>
Hi Michal,
Thanks very much for taking a look!
On 5/10/2024 3:37 PM, Michal Orzel wrote:
> Hi Henry,
>
> On 26/04/2024 05:14, Henry Wang wrote:
>> There are use cases (for example using the PV driver) in Dom0less
>> setup that require Dom0less DomUs start immediately with Dom0, but
>> initialize XenStore later after Dom0's successful boot and call to
>> the init-dom0less application.
>>
>> An error message can seen from the init-dom0less application on
>> 1:1 direct-mapped domains:
>> ```
>> Allocating magic pages
>> memory.c:238:d0v0 mfn 0x39000 doesn't belong to d1
>> Error on alloc magic pages
>> ```
>> This is because currently the magic pages for Dom0less DomUs are
>> populated by the init-dom0less app through populate_physmap(), and
>> populate_physmap() automatically assumes gfn == mfn for 1:1 direct
>> mapped domains. This cannot be true for the magic pages that are
>> allocated later from the init-dom0less application executed in Dom0.
>> For domain using statically allocated memory but not 1:1 direct-mapped,
>> similar error "failed to retrieve a reserved page" can be seen as the
>> reserved memory list is empty at that time.
>>
>> To solve above issue, this commit allocates the magic pages for
>> Dom0less DomUs at the domain construction time. The base address/PFN
>> of the magic page region will be noted and communicated to the
>> init-dom0less application in Dom0.
>>
>> Reported-by: Alec Kwapis <alec.kwapis@medtronic.com>
>> Suggested-by: Daniel P. Smith <dpsmith@apertussolutions.com>
>> Signed-off-by: Henry Wang <xin.wang2@amd.com>
>> ---
>> tools/libs/guest/xg_dom_arm.c | 1 -
>> xen/arch/arm/dom0less-build.c | 22 ++++++++++++++++++++++
>> xen/include/public/arch-arm.h | 1 +
>> 3 files changed, 23 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/libs/guest/xg_dom_arm.c b/tools/libs/guest/xg_dom_arm.c
>> index 2fd8ee7ad4..8cc7f27dbb 100644
>> --- a/tools/libs/guest/xg_dom_arm.c
>> +++ b/tools/libs/guest/xg_dom_arm.c
>> @@ -25,7 +25,6 @@
>>
>> #include "xg_private.h"
>>
>> -#define NR_MAGIC_PAGES 4
> Moving only this macro to arch-arm.h while leaving the offsets does not make much sense to me.
> I think they all should be moved. This would also allow init-dom0less.h not to re-define XENSTORE_PFN_OFFSET.
Sounds good. Will do in v2.
>> #define CONSOLE_PFN_OFFSET 0
>> #define XENSTORE_PFN_OFFSET 1
>> #define MEMACCESS_PFN_OFFSET 2
>> diff --git a/xen/arch/arm/dom0less-build.c b/xen/arch/arm/dom0less-build.c
>> index fb63ec6fd1..40dc85c759 100644
>> --- a/xen/arch/arm/dom0less-build.c
>> +++ b/xen/arch/arm/dom0less-build.c
>> @@ -834,11 +834,33 @@ static int __init construct_domU(struct domain *d,
>>
>> if ( kinfo.dom0less_feature & DOM0LESS_XENSTORE )
>> {
>> + struct page_info *magic_pg;
>> + mfn_t mfn;
>> + gfn_t gfn;
>> +
>> ASSERT(hardware_domain);
>> rc = alloc_xenstore_evtchn(d);
>> if ( rc < 0 )
>> return rc;
>> d->arch.hvm.params[HVM_PARAM_STORE_PFN] = ~0ULL;
>> +
>> + d->max_pages += NR_MAGIC_PAGES;
>> + magic_pg = alloc_domheap_pages(d, get_order_from_pages(NR_MAGIC_PAGES), 0);
> 80 char exceeded
Ooops, I am sorry. Will fix in v2.
>> + if ( magic_pg == NULL )
>> + return -ENOMEM;
>> +
>> + mfn = page_to_mfn(magic_pg);
>> + if ( !is_domain_direct_mapped(d) )
>> + gfn = gaddr_to_gfn(GUEST_MAGIC_BASE);
>> + else
>> + gfn = gaddr_to_gfn(mfn_to_maddr(mfn));
>> +
>> + rc = guest_physmap_add_pages(d, gfn, mfn, NR_MAGIC_PAGES);
>> + if ( rc )
>> + {
>> + free_domheap_pages(magic_pg, get_order_from_pages(NR_MAGIC_PAGES));
>> + return rc;
>> + }
> Please create a function alloc_magic_pages to encapsulate the above block.
Sure. Will do.
Kind regards,
Henry
next prev parent reply other threads:[~2024-05-10 7:42 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 [this message]
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
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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