Re: [Xen-devel] The size of memory is wrong inside of virtual machine(VM) when using OVMF

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Jun 01, 2015 at 09:13:08AM +0000, Maoming wrote:
> Hi all:
>        I encountered a troublesome problem about OVMF.
>        I used OVMF.fd as a BIOS of virtual machine(VM).
> 
>        1ãmy environment:
>        xen_version            : 4.6-unstable
>        I git clone xen from git://xenbits.xen.org/xen.git. configure it and 
> parameters as below:
>        ./configure --prefix=/usr/ --libdir=/usr/lib/  --enable-ovmf then make 
> && make install, after that I reboot my host OS(suse11sp3).
> 
>         There is a same problem in KVM too.
> 
>        2ãproblem:
>        I started a VM whose memory is 64G in the host.
>        The size of memory inside of the VM is wrong while it is OK when I 
> check it in the host using "xl list".
>        But, when I changed the memory to 63G,it was both OK.
>        (1)64G memory
>        inside of VM using "free" to check:
>                     total       used       free     shared    buffers     
> cached
>        Mem:       3715640     495916    3219724          0      22060     
> 175136
>        -/+ buffers/cache:     298720    3416920
>        Swap:      4046840          0    4046840
>        It is only 3.5G.
> 
>        in the host using "xl list" to check:
>        Name                                        ID   Mem VCPUs      State  
>  Time(s)
>        Domain-0                                     0  3055    16     r-----  
>    861.2
>        redhat                                       4 65536     2     r-----  
>      5.9
> 
>        (2)63G memory
>        inside of VM using "free" to check:
>                     total       used       free     shared    buffers     
> cached
>        Mem:      64918224    1083912   63834312          0      22188     
> 175344
>        -/+ buffers/cache:     886380   64031844
>        Swap:      4046840          0    4046840
>        It is OK.
> 
>        in the host using "xl list" to check:
>        Name                                        ID   Mem VCPUs      State  
>  Time(s)
>        Domain-0                                     0  3055    16     r-----  
>    821.2
>        redhat                                       3 64512     2     -b----  
>     48.5
> 
>        3ãmy cfg file:
>        builder = "hvm"
>        name = "redhat"
>        memory = 65536
>        maxmem = 65536
>        vcpus = 2
>        bios = "ovmf"
>        boot = "dc"
>        sdl=0
>        disk = [ 'file:/test/image/redhat6_3.img,xvda,w' ]
>        vnc = 1
>        vnclisten = '9.61.1.31'
>        vncdisplay = 0
> 
>        Any thought on this?
>        Any help will be appreciated.
>        If you need some other information, please let me know. :)
> 

It looks like there is some kind of truncation inside OVMF. But I don't
have a test box that has so much memory so I cannot try it myself.

Since it manifests on both Xen and KVM I don't really have an idea about
what's going on.

The only thing I can say is that the tested OVMF tree for Xen is 

http://xenbits.xen.org/gitweb/?p=osstest/ovmf.git;a=summary
xen-tested-master

The one in xen.git is updated periodically. Make sure you use our
latest tested branch so you can get fixes from upstream.

Wei.

>        Thanks!
>          -mao

> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel


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