[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 4/9] xen/pvh: Bootstrap PVH guest
On 03/02/17 17:20, Boris Ostrovsky wrote: > >>> + >>> + __HEAD >>> + >>> +/* Entry point for PVH guests. */ >> Could you add some comments about register conetnts at entry? > > Reference to Xen's docs/misc/hvmlite.markdown would be sifficient? I think the corresponding lines should be copied to this source file. It is inconvenient to have to get the Xen repostory for this information. >>> +gdt: >>> + .word gdt_end - gdt >>> + .long _pa(gdt) >> This is a rather strange construct: the NULL descriptor of the >> GDT being used as space for lgdt operand. >> >>> + .word 0 >>> + .quad 0x0000000000000000 /* NULL descriptor */ >> And this comment is wrong: the NULL descriptor is at "gdt:". > > I'll change it to: > > gdt: > .word gdt_end - gdt_start > .long _pa(gdt_start) > .word 0 > gdt_start: > .quad 0x0000000000000000 /* NULL descriptor */ > .quad 0x0000000000000000 /* reserved */ Much better. :-) > #ifdef CONFIG_X86_64 > .quad 0x00af9a000000ffff /* __KERNEL_CS */ > #else > .quad 0x00cf9a000000ffff /* __KERNEL_CS */ > #endif > .quad 0x00cf92000000ffff /* __KERNEL_DS */ > gdt_end: > > >> >>> +#ifdef CONFIG_X86_64 >>> + .quad 0x00af9a000000ffff /* __KERNEL_CS */ >> Mind adding comments about the semantics of those constants? >> Or use GDT_ENTRY() macro? >> >>> +#else >>> + .quad 0x00cf9a000000ffff /* __KERNEL_CS */ >>> +#endif >>> + .quad 0x00cf92000000ffff /* __KERNEL_DS */ >>> +gdt_end: >>> + >>> + .bss >>> + .balign 4 >>> +early_stack: >>> + .fill 16, 1, 0 >> Is the stack size large enough? With a hypercall being executed in >> xen_prepare_pvh() I doubt this will be okay. > > What do you think it should be then? I didn't check the disassembly, but even if it is okay right now the needed stack size will depend on the compiler used. I'd rather use a larger size (e.g. 256 bytes). Maybe its even possible to reuse initial_stack, but I haven't verified that. Juergen _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |