Re: [PATCH v1 7/9] memory: introduce RAM_NORESERVE and wire it up in qemu_ram_mmap()

[David Hildenbrand]

On 02.03.21 18:32, Peter Xu wrote:
> On Tue, Feb 09, 2021 at 02:49:37PM +0100, David Hildenbrand wrote:
> > @@ -899,13 +899,17 @@ int kvm_s390_mem_op_pv(S390CPU *cpu, uint64_t offset, 
> > void *hostbuf,
> >    * to grow. We also have to use MAP parameters that avoid
> >    * read-only mapping of guest pages.
> >    */
> > -static void *legacy_s390_alloc(size_t size, uint64_t *align, bool shared)
> > +static void *legacy_s390_alloc(size_t size, uint64_t *align, bool shared,
> > +                               bool noreserve)
> >   {
> >       static void *mem;
> >   
> >       if (mem) {
> >           /* we only support one allocation, which is enough for initial ram */
> >           return NULL;
> > +    } else if (noreserve) {
> > +        error_report("Skipping reservation of swap space is not supported.");
> > +        return NULL
>
> Semicolon missing.

Thanks for catching that!

> >       }
> >   
> >       mem = mmap((void *) 0x800000000ULL, size,
> > diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
> > index b50dc86a3c..bb99843106 100644
> > --- a/util/mmap-alloc.c
> > +++ b/util/mmap-alloc.c
> > @@ -20,6 +20,7 @@
> >   #include "qemu/osdep.h"
> >   #include "qemu/mmap-alloc.h"
> >   #include "qemu/host-utils.h"
> > +#include "qemu/error-report.h"
> >   
> >   #define HUGETLBFS_MAGIC       0x958458f6
> >   
> > @@ -174,12 +175,18 @@ void *qemu_ram_mmap(int fd,
> >                       size_t align,
> >                       bool readonly,
> >                       bool shared,
> > -                    bool is_pmem)
> > +                    bool is_pmem,
> > +                    bool noreserve)
>
> Maybe at some point we should use flags too here to cover all bools.

Right. I guess the main point was to not reuse RAM_XXX.

Should I introduce RAM_MMAP_XXX ?

Thanks!

--
Thanks,

David / dhildenb