"H. Peter Anvin" <hpa@xxxxxxxxx> writes: > Eric W. Biederman wrote: >> When in PAE mode we require that the user kernel divide to be >> on a 1G boundary. The 2G/2G split does not have that property >> so require !X86_PAE > > ????? > > -hpa >From arch/i386/Kconfig: > > choice > depends on EXPERIMENTAL > prompt "Memory split" if EMBEDDED > default VMSPLIT_3G > help > Select the desired split between kernel and user memory. > > If the address range available to the kernel is less than the > physical memory installed, the remaining memory will be available > as "high memory". Accessing high memory is a little more costly > than low memory, as it needs to be mapped into the kernel first. > Note that increasing the kernel address space limits the range > available to user programs, making the address space there > tighter. Selecting anything other than the default 3G/1G split > will also likely make your kernel incompatible with binary-only > kernel modules. > > If you are not absolutely sure what you are doing, leave this > option alone! > > config VMSPLIT_3G > bool "3G/1G user/kernel split" > config VMSPLIT_3G_OPT > depends on !HIGHMEM > bool "3G/1G user/kernel split (for full 1G low memory)" > config VMSPLIT_2G > depends on !X86_PAE > bool "2G/2G user/kernel split" > config VMSPLIT_1G > bool "1G/3G user/kernel split" > endchoice > > config PAGE_OFFSET > hex > default 0xB0000000 if VMSPLIT_3G_OPT > default 0x78000000 if VMSPLIT_2G > default 0x40000000 if VMSPLIT_1G > default 0xC0000000 The default PAGE_OFFSET is at 0x7800000 for the 2G/2G split. All of these options were originally !X86_PAE, I assume the intention was to be able to have 2G of RAM without needing high memory. I don't really care I just saw the problem and decided to prevent people trying a combination that simply doesn't work. Eric _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
