Re: [Xen-devel] [v8][PATCH 07/17] hvmloader/util: get reserved device memory maps

["Chen, Tiejun" <tiejun.chen@xxxxxxxxx>]

On 2014/12/2 16:59, Tian, Kevin wrote:
> > From: Chen, Tiejun
> > Sent: Monday, December 01, 2014 5:24 PM
> >
> > We need to use reserved device memory maps with multiple times, so
> > provide just one common function should be friend.
> >
> > Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxx>
> > ---
> >   tools/firmware/hvmloader/util.c | 59
> > +++++++++++++++++++++++++++++++++++++++++
> >   tools/firmware/hvmloader/util.h |  2 ++
> >   2 files changed, 61 insertions(+)
> >
> > diff --git a/tools/firmware/hvmloader/util.c b/tools/firmware/hvmloader/util.c
> > index 80d822f..dd81fb6 100644
> > --- a/tools/firmware/hvmloader/util.c
> > +++ b/tools/firmware/hvmloader/util.c
> > @@ -22,11 +22,14 @@
> >   #include "config.h"
> >   #include "hypercall.h"
> >   #include "ctype.h"
> > +#include "errno.h"
> >   #include <stdint.h>
> >   #include <xen/xen.h>
> >   #include <xen/memory.h>
> >   #include <xen/sched.h>
> >
> > +struct xen_reserved_device_memory *rdm_map;
> > +
> >   void wrmsr(uint32_t idx, uint64_t v)
> >   {
> >       asm volatile (
> > @@ -828,6 +831,62 @@ int hpet_exists(unsigned long hpet_base)
> >       return ((hpet_id >> 16) == 0x8086);
> >   }
> >
> > +static int
> > +get_reserved_device_memory_map(struct xen_reserved_device_memory
> > entries[],
> > +                               uint32_t *max_entries)
> > +{
> > +    int rc;
> > +    struct xen_reserved_device_memory_map xrdmmap = {
> > +        .domid = DOMID_SELF,
> > +        .nr_entries = *max_entries
> > +    };
> > +
> > +    set_xen_guest_handle(xrdmmap.buffer, entries);
> > +
> > +    rc = hypercall_memory_op(XENMEM_reserved_device_memory_map,
> > &xrdmmap);
> > +    *max_entries = xrdmmap.nr_entries;
> > +
> > +    return rc;
> > +}
> > +
> > +/*
> > + * Getting all reserved device memory map info in case of hvmloader.
> > + * We just return zero for any failed cases, and this means we
> > + * can't further handle any reserved device memory.
> > + */
> > +unsigned int hvm_get_reserved_device_memory_map(void)
> > +{
> > +    static unsigned int nr_entries = 0;
> > +    int rc = get_reserved_device_memory_map(rdm_map, &nr_entries);
> > +
> if this function is aimed to be invoked once, just check wheher rdm_map
> is valid instead of always issuing a new call.
As I remember Jan thought this doesn't cost more even in multiple times.

> > +    if ( rc == -ENOBUFS )
> > +    {
> > +        rdm_map = mem_alloc(nr_entries*sizeof(struct
> > xen_reserved_device_memory),
> > +                            0);
> > +        if ( rdm_map )
> > +        {
> > +            rc = get_reserved_device_memory_map(rdm_map,
> > &nr_entries);
> > +            if ( rc )
> > +            {
> > +                printf("Could not get reserved dev memory info on
> > domain");
> > +                return 0;
> why return '0' at failure?
In out real case, we don't want to handle more since its already fine 
with one message.
Thanks
Tiejun

> > +            }
> > +        }
> > +        else
> > +        {
> > +            printf("No space to get reserved dev memory maps!\n");
> > +            return 0;
> > +        }
> > +    }
> > +    else if ( rc )
> > +    {
> > +        printf("Could not get reserved dev memory info on domain");
> > +        return 0;
> > +    }
> > +
> > +    return nr_entries;
> > +}
> > +
> >   /*
> >    * Local variables:
> >    * mode: C
> > diff --git a/tools/firmware/hvmloader/util.h
> > b/tools/firmware/hvmloader/util.h
> > index a70e4aa..e4f1851 100644
> > --- a/tools/firmware/hvmloader/util.h
> > +++ b/tools/firmware/hvmloader/util.h
> > @@ -241,6 +241,8 @@ int build_e820_table(struct e820entry *e820,
> >                        unsigned int bios_image_base);
> >   void dump_e820_table(struct e820entry *e820, unsigned int nr);
> >
> > +unsigned int hvm_get_reserved_device_memory_map(void);
> > +
> >   #ifndef NDEBUG
> >   void perform_tests(void);
> >   #else
> > --
> > 1.9.1
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