Re: [Xen-users] DomU sees only 512MB RAM with PCI-passthrough

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Wed, Dec 19, 2012 at 10:20:33PM +0100, Christian Holpert wrote:
> At 18:38 19.12.2012, you wrote:
> >> >          e820: update [mem 0x00000000-0x0000ffff] usable ==> reserved
> >> >          e820: remove [mem 0x000a0000-0x000fffff] usable
> >> >         -e820: last_pfn = 0x80000 max_arch_pfn = 0x1000000
> >> >         +e820: last_pfn = 0x20000 max_arch_pfn = 0x1000000
> >>
> >> I think the kernel has done the correct thing with the supplied e820 map.
> >>
> >> > On the libxl side with pci I also see:
> >> >         +libxl: debug:
> >libxl_pci.c:85:libxl__create_pci_backend: Creating pci backend
> >> >         +libxl: debug: libxl_x86.c:82:e820_sanitize: Memory:
> >2097152kB End of RAM: 0x20000 (PFN) Delta: 1572864kB, PCI start:
> >524288kB (0x20000 PFN), Balloon 0kB
> >> >         +
> >> >         +libxl: debug: libxl_x86.c:201:e820_sanitize: : [0 -> 20000] RAM
> >>
> >> This is the 512 MiB limit here, so I think the bug is in libxl.
> >
> >Correct.
> >>
> >> Why has it placed the PCI window at 512 MiB anyway?  3 GiB would be more
> >> conventional.
> >
> >It "copies" what the E820 is and tries it best to sanitize it.
> >
> >But it looks to have missed the "RAM" chunks in from the 0->3GB.
> >
> >However, it should have made the 'Balloon' be much much bigger value.
> >Something is off there. What type of machine is this? An Intel
> >DQSW..something?
> 
> 
> Intel Core i5-3570 (Ivy Bridge Generation)
> ASRock Q77M vPro
> 16GB RAM
> 
> /proc/cpuinfo
> processor       : 0
> vendor_id       : GenuineIntel
> cpu family      : 6
> model           : 58
> model name      : Intel(R) Core(TM) i5-3570 CPU @ 3.40GHz
> stepping        : 9
> microcode       : 0x10
> cpu MHz         : 3392.416
> cache size      : 6144 KB
> physical id     : 0
> siblings        : 1
> core id         : 0
> cpu cores       : 1
> apicid          : 0
> initial apicid  : 0
> fdiv_bug        : no
> hlt_bug         : no
> f00f_bug        : no
> coma_bug        : no
> fpu             : yes
> fpu_exception   : yes
> cpuid level     : 13
> wp              : yes
> flags           : fpu de tsc msr pae cx8 apic cmov pat clflush acpi
> mmx fxsr sse sse2 ss ht nx constant_tsc nonstop_tsc pni pclmulqdq
> monitor est ssse3 sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes
> xsave avx f16c rdrand hypervisor ida arat epb xsaveopt pln pts
> dtherm fsgsbase erms
> bogomips        : 6784.83
> clflush size    : 64
> cache_alignment : 64
> address sizes   : 36 bits physical, 48 bits virtual
> power management:
> 
> repeated as expected for quad-core.
> 
> Have tried to move to xen-4.2.1 today, but no change:
> xen ~ # xl list
> Name                                        ID   Mem VCPUs      State   
> Time(s)
> Domain-0                                     0  9082     4     r-----      
> 53.8
> colin                                        1  2048     3     -b----      
> 73.9
> nodi                                         2   512     2     -b----     
> 110.2
> [...]
> 
> BTW: When I shutdown this domain now, I keep some leftovers:
> xen xen # xl list
> Name                                        ID   Mem VCPUs      State   
> Time(s)
> Domain-0                                     0  7535     4     r-----      
> 78.2
> colin                                        1  2048     3     -b----      
> 91.6
> (null)                                       2     6     2     --ps-d     
> 144.6
> print                                        3  2048     3     -b----       
> 5.0
> web                                          4  1024     2     -b----      
> 12.7
> nodi                                         5   512     2     ---s--      
> 52.9
> xen xen #
> 
> xen xen # xl list
> Name                                        ID   Mem VCPUs      State   
> Time(s)
> Domain-0                                     0  7529     4     r-----      
> 85.2
> colin                                        1  2048     3     -b----     
> 102.3
> (null)                                       2     6     2     --ps-d     
> 144.6
> print                                        3  2048     3     -b----       
> 5.1
> web                                          4  1024     2     -b----      
> 13.1
> (null)                                       5     6     2     --ps-d      
> 52.9
> nodi                                         6   512     2     r-----      
> 13.6
> xen xen #
> 
> xen xen # xl info 2
> host                   : xen
> release                : 3.4.11-gentoo
> version                : #7 SMP Mon Dec 3 20:37:13 CET 2012
> machine                : i686
> nr_cpus                : 4
> max_cpu_id             : 3
> nr_nodes               : 1
> cores_per_socket       : 4
> threads_per_core       : 1
> cpu_mhz                : 3392
> hw_caps                : 
> bfebfbff:28100000:00000000:00007f40:77bae3ff:00000000:00000001:00000281
> virt_caps              : hvm hvm_directio
> total_memory           : 15778
> free_memory            : 2446
> sharing_freed_memory   : 0
> sharing_used_memory    : 0
> free_cpus              : 0
> xen_major              : 4
> xen_minor              : 2
> xen_extra              : .1
> xen_caps               : xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p
> xen_scheduler          : credit
> xen_pagesize           : 4096
> platform_params        : virt_start=0xf5800000
> xen_changeset          : unavailable
> xen_commandline        : vtd=1 iommu=1 vga=gfx-1024x768x16 msi=1
> cc_compiler            : gcc (Gentoo 4.7.2 p1.3, pie-0.5.5) 4.7.2
> cc_compile_by          :
> cc_compile_domain      : APO43287A.LOCAL
> cc_compile_date        : Wed Dec 19 20:22:58 CET 2012
> xend_config_format     : 4
> xen xen #
> 
> Never seen this with 4.2.0.

Oh, so you see it with Xen 4.3? Could you pls provide the output
of 'xl' with those nice verbose outputs with the same guest config.

That would help a lot.

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