[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] query on physical memory map for Xen?
Just curious, can anyone give a hint on where this 16GB max physical memory is defined? Doing some random search by strings I found these: #define MAXMEM 0x3fffffffffffUL #define MAXMEM (__FIXADDR_TOP-__PAGE_OFFSET-__VMALLOC_RESERVE) #define MAXMEM_PFN PFN_DOWN(MAXMEM) #define ACPI_MEM_LIST_MAX 6 #define NR_NODE_MEMBLKS (MAX_NUMNODES*2) #define EFI_MAX_MEMORY_TYPE 14 #define PCI_X_CMD_MAX_READ 0x000c /* Max Memory Read Byte Count */ #define PCI_X_STATUS_MAX_READ 0x00600000 /* Designed Max Memory Read Count */ #define GEO_TYPE_MAX (GEO_TYPE_MEM+1) #define NR_NODE_MEMBLKS (MAX_NUMNODES*2) *max_mfn = xc_memory_op(xc_handle, XENMEM_maximum_ram_page, NULL); #define EFI_MAX_MEMORY_TYPE 14 #define MAXMEM 0x3fffffffffffUL * KEXEC_SOURCE_MEMORY_LIMIT maximum page get_free_page can return. #define MAXMEM (__FIXADDR_TOP-__PAGE_OFFSET-__VMALLOC_RESERVE) #define MAXMEM_PFN PFN_DOWN(MAXMEM) * KEXEC_SOURCE_MEMORY_LIMIT maximum page get_free_page can return. #define ACPI_MEM_LIST_MAX 6 #define XENMEM_maximum_ram_page 2 #define XENMEM_maximum_reservation 4 #define XENMEM_maximum_gpfn 14 #define NR_NODE_MEMBLKS (MAX_NUMNODES*2) #define EFI_MAX_MEMORY_TYPE 14 #define GEO_TYPE_MAX (GEO_TYPE_MEM+1) #define NR_NODE_MEMBLKS (MAX_NUMNODES*2) Not sure which one maps to this 16GB thing? Thanks for the sharing :-). On Fri, Apr 11, 2008 at 2:54 PM, Keir Fraser <keir.fraser@xxxxxxxxxxxxx> wrote: > On 11/4/08 07:14, "pradeep singh rautela" <rautelap@xxxxxxxxx> wrote: > > > Based on my understanding of the Xen code, I have a small query for you > all. > > > > Xen hypervisor can access only a max of 16GB of physical memory > > directly on x86 architecture. > > Is this correct inference? > > > > So does Xen hypervisor cannot touch memory about 16G directly? Does it > > employ some kind of temporary mapping like linux kernel to access > > memory above 16G then? > > 32-bit Xen does not use memory above 16GB at all. 64-bit Xen can use any > amount of memory, and is able to keep a permanent mapping of all of it. > > -- Keir > > > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel > -- Regards, Peter Teoh _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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