Re: Discussion of Xenheap problems on AArch64

From: Julien Grall <julien@xen.org>
To: Henry Wang <Henry.Wang@arm.com>,
	"sstabellini@kernel.org" <sstabellini@kernel.org>,
	"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Wei Chen <Wei.Chen@arm.com>, Penny Zheng <Penny.Zheng@arm.com>,
	Bertrand Marquis <Bertrand.Marquis@arm.com>
Subject: Re: Discussion of Xenheap problems on AArch64
Date: Thu, 13 May 2021 19:18:12 +0100	[thread overview]
Message-ID: <ba1bc084-5a5b-1410-acba-33bfca7c4f6a@xen.org> (raw)
In-Reply-To: <PA4PR08MB6253F85E184CA51BDB99786992539@PA4PR08MB6253.eurprd08.prod.outlook.com>



On 11/05/2021 02:11, Henry Wang wrote:
> Hi Julien,

Hi Henry,

> 
>> From: Julien Grall <julien@xen.org>
>> Hi Henry,
>>
>> On 07/05/2021 05:06, Henry Wang wrote:
>>>> From: Julien Grall <julien@xen.org>
>>>> On 28/04/2021 10:28, Henry Wang wrote:
>> [...]
>>
>>> when I continue booting Xen, I got following error log:
>>>
>>> (XEN) CPU:    0
>>> (XEN) PC:     00000000002b5a5c alloc_boot_pages+0x94/0x98
>>> (XEN) LR:     00000000002ca3bc
>>> (XEN) SP:     00000000002ffde0
>>> (XEN) CPSR:   600003c9 MODE:64-bit EL2h (Hypervisor, handler)
>>> (XEN)
>>> (XEN)   VTCR_EL2: 80000000
>>> (XEN)  VTTBR_EL2: 0000000000000000
>>> (XEN)
>>> (XEN)  SCTLR_EL2: 30cd183d
>>> (XEN)    HCR_EL2: 0000000000000038
>>> (XEN)  TTBR0_EL2: 000000008413c000
>>> (XEN)
>>> (XEN)    ESR_EL2: f2000001
>>> (XEN)  HPFAR_EL2: 0000000000000000
>>> (XEN)    FAR_EL2: 0000000000000000
>>> (XEN)
>>> (XEN) Xen call trace:
>>> (XEN)    [<00000000002b5a5c>] alloc_boot_pages+0x94/0x98 (PC)
>>> (XEN)    [<00000000002ca3bc>] setup_frametable_mappings+0xa4/0x108
>> (LR)
>>> (XEN)    [<00000000002ca3bc>] setup_frametable_mappings+0xa4/0x108
>>> (XEN)    [<00000000002cb988>] start_xen+0x344/0xbcc
>>> (XEN)    [<00000000002001c0>]
>> arm64/head.o#primary_switched+0x10/0x30
>>> (XEN)
>>> (XEN) ****************************************
>>> (XEN) Panic on CPU 0:
>>> (XEN) Xen BUG at page_alloc.c:432
>>> (XEN) ****************************************
>>
>> This is happening without my patch series applied, right? If so, what
>> happen if you apply it?
> 
> No, I am afraid this is with your patch series applied, and that is why I
> am a little bit confused about the error log...

You are hitting the BUG() at the end of alloc_boot_pages(). This is hit 
because the boot allocator couldn't allocate memory for your request.

Would you be able to apply the following diff and paste the output here?

diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index ace6333c18ea..dbb736fdb275 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -329,6 +329,8 @@ void __init init_boot_pages(paddr_t ps, paddr_t pe)
      if ( pe <= ps )
          return;

+    printk("%s: ps %"PRI_paddr" pe %"PRI_paddr"\n", __func__, ps, pe);
+
      first_valid_mfn = mfn_min(maddr_to_mfn(ps), first_valid_mfn);

      bootmem_region_add(ps >> PAGE_SHIFT, pe >> PAGE_SHIFT);
@@ -395,6 +397,8 @@ mfn_t __init alloc_boot_pages(unsigned long nr_pfns, 
unsigned long pfn_align)
      unsigned long pg, _e;
      unsigned int i = nr_bootmem_regions;

+    printk("%s: nr_pfns %lu pfn_align %lu\n", __func__, nr_pfns, 
pfn_align);
+
      BUG_ON(!nr_bootmem_regions);

      while ( i-- )

Cheers,

-- 
Julien Grall

