On Mon, 2015-10-26 at 16:03 +0000, Anthony PERARD wrote:
> Signed-off-by: Anthony PERARD <anthony.per...@citrix.com>
> ---
> tools/firmware/hvmloader/hvmloader.c | 69
> +++++++++++++++++++++++++++++++++++-
> 1 file changed, 68 insertions(+), 1 deletion(-)
>
> diff --git a/tools/firmware/hvmloader/hvmloader.c
> b/tools/firmware/hvmloader/hvmloader.c
> index 716d03c..9df12ac 100644
> --- a/tools/firmware/hvmloader/hvmloader.c
> +++ b/tools/firmware/hvmloader/hvmloader.c
> @@ -62,7 +62,7 @@ asm (
> " mov %ax,%ss \n"
> /* Initialise all 32-bit GPRs to zero. */
> " xor %eax,%eax \n"
> - " xor %ebx,%ebx \n"
> + /* Keep ebx, for HVMLite start info */
Isn't this now an ABI between the tools and HVM loader, which is embedded
in the more formal PVH/HVMLite startup protocol? In which case hopefully
there is somewhere it can be documented. Is a HVMlite/PVH guest allowed to
assume anything about %ebx, those sorts of questions need to be considered.
> " xor %ecx,%ecx \n"
> " xor %edx,%edx \n"
> " xor %esp,%esp \n"
> @@ -249,15 +249,82 @@ static void acpi_enable_sci(void)
> BUG_ON(!(pm1a_cnt_val & ACPI_PM1C_SCI_EN));
> }
>
> +static const char *module_list_order = NULL;
> +void cmdline_parser(const char *the_cmdline)
I'll leave this until we've decided if this approach is the one we want.
> int main(void)
> {
> const struct bios_config *bios;
> int acpi_enabled;
> + const struct hvm_start_info *hvmlite_start_info;
> +
> + /* Load hvmlite start info pointer from ebx. */
> + asm volatile ( "mov %%ebx,%0" : "=r" (hvmlite_start_info) );
The stub which calls main should perhaps arrange for this to be in a
register which ends up being a parameter to this struct. I think otherwise
nothing ensures that the function prolog hasn't clobbered %ebx already.
>
> /* Initialise hypercall stubs with RET, rendering them no-ops. */
> memset((void *)HYPERCALL_PHYSICAL_ADDRESS, 0xc3 /* RET */,
> PAGE_SIZE);
>
> printf("HVM Loader\n");
> + BUG_ON(hvmlite_start_info->magic != HVM_START_MAGIC_VALUE);
> + printf("cmdline: %s\n", (char*)hvmlite_start_info->cmdline_paddr);
> + cmdline_parser((char*)hvmlite_start_info->cmdline_paddr);
>
> init_hypercalls();
>
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