Re: [PATCH v4 10/19] xen: setup hypercall page for PVH

[Juergen Gross <jgross@suse.com>]

On 15/11/2018 09:33, Roger Pau Monné wrote:
> On Fri, Nov 02, 2018 at 01:37:29PM +0100, Juergen Gross wrote:
>> Add the needed code to setup the hypercall page for calling into the
>> Xen hypervisor.
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
> 
> Thanks, LGTM, just one suggestion and one question.
> 
>> ---
>> V3: grub_xen_early_halt->grub_xen_panic (Roger Pau Monné)
>>     issue panic message (Roger Pau Monné)
>>     rewrite grub_xen_hypercall to avoid register variables (Daniel Kiper)
>> ---
>>  grub-core/kern/i386/xen/pvh.c | 69 +++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 69 insertions(+)
>>
>> diff --git a/grub-core/kern/i386/xen/pvh.c b/grub-core/kern/i386/xen/pvh.c
>> index ac6181f4e..7e90a4538 100644
>> --- a/grub-core/kern/i386/xen/pvh.c
>> +++ b/grub-core/kern/i386/xen/pvh.c
>> @@ -20,14 +20,83 @@
>>  #include <grub/misc.h>
>>  #include <grub/memory.h>
>>  #include <grub/mm.h>
>> +#include <grub/i386/cpuid.h>
>> +#include <grub/i386/io.h>
>>  #include <grub/xen.h>
>>  #include <grub/machine/kernel.h>
>>  
>> +#define XEN_CONSOLE_PORT   0xe9
> 
> This is now part of the public headers (XEN_HVM_DEBUGCONS_IOPORT) if
> you wish to pick it up from there.

I don't want to import headers from Xen unstable, so I'll add just that
define (and the associated comment) to include/xen/arch-x86/xen.h

> 
>> +
>>  grub_uint64_t grub_rsdp_addr;
>>  
>> +static char hypercall_page[GRUB_XEN_PAGE_SIZE]
>> +  __attribute__ ((aligned (GRUB_XEN_PAGE_SIZE)));
>> +
>> +static grub_uint32_t xen_cpuid_base;
>> +
>> +static void
>> +grub_xen_panic (const char *msg)
>> +{
>> +  const char *c;
>> +
>> +  for (c = msg; *c; c++)
>> +    grub_outb (*c, XEN_CONSOLE_PORT);
>> +
>> +  asm volatile ("hlt");
> 
> Should this be "cli; hlt;", or does grub always runs with interrupt flag
> clear?

Good point. Maybe I should even add a loop around the hlt.


Juergen


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