Messages in this thread Patch in this message | | | Subject | Re: [RFC PATCH 10/16] xen/balloon: support ballooning in xenhost_t | From | Juergen Gross <> | Date | Mon, 17 Jun 2019 11:28:12 +0200 |
| |
On 09.05.19 19:25, Ankur Arora wrote: > Xen ballooning uses hollow struct pages (with the underlying GFNs being > populated/unpopulated via hypercalls) which are used by the grant logic > to map grants from other domains. > > This patch allows the default xenhost to provide an alternate ballooning > allocation mechanism. This is expected to be useful for local xenhosts > (type xenhost_r0) because unlike Xen, where there is an external > hypervisor which can change the memory underneath a GFN, that is not > possible when the hypervisor is running in the same address space > as the entity doing the ballooning. > > Co-developed-by: Ankur Arora <ankur.a.arora@oracle.com> > Signed-off-by: Joao Martins <joao.m.martins@oracle.com> > Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com> > --- > arch/x86/xen/enlighten_hvm.c | 7 +++++++ > arch/x86/xen/enlighten_pv.c | 8 ++++++++ > drivers/xen/balloon.c | 19 ++++++++++++++++--- > drivers/xen/grant-table.c | 4 ++-- > drivers/xen/privcmd.c | 4 ++-- > drivers/xen/xen-selfballoon.c | 2 ++ > drivers/xen/xenbus/xenbus_client.c | 6 +++--- > drivers/xen/xlate_mmu.c | 4 ++-- > include/xen/balloon.h | 4 ++-- > include/xen/xenhost.h | 19 +++++++++++++++++++ > 10 files changed, 63 insertions(+), 14 deletions(-) > > diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c > index 5ef4d6ad920d..08becf574743 100644 > --- a/drivers/xen/balloon.c > +++ b/drivers/xen/balloon.c > @@ -63,6 +63,7 @@ > #include <asm/tlb.h> > > #include <xen/interface/xen.h> > +#include <xen/xenhost.h> > #include <asm/xen/hypervisor.h> > #include <asm/xen/hypercall.h> > > @@ -583,12 +584,21 @@ static int add_ballooned_pages(int nr_pages) > * @pages: pages returned > * @return 0 on success, error otherwise > */ > -int alloc_xenballooned_pages(int nr_pages, struct page **pages) > +int alloc_xenballooned_pages(xenhost_t *xh, int nr_pages, struct page **pages) > { > int pgno = 0; > struct page *page; > int ret; > > + /* > + * xenmem transactions for remote xenhost are disallowed. > + */ > + if (xh->type == xenhost_r2) > + return -EINVAL;
Why don't you set a dummy function returning -EINVAL into the xenhost_r2 structure instead?
> + > + if (xh->ops->alloc_ballooned_pages) > + return xh->ops->alloc_ballooned_pages(xh, nr_pages, pages); > +
Please make alloc_xenballooned_pages() an inline wrapper and use the current implmentaion as the default. This avoids another if ().
> mutex_lock(&balloon_mutex); > > balloon_stats.target_unpopulated += nr_pages; > @@ -620,7 +630,7 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages) > return 0; > out_undo: > mutex_unlock(&balloon_mutex); > - free_xenballooned_pages(pgno, pages); > + free_xenballooned_pages(xh, pgno, pages); > return ret; > } > EXPORT_SYMBOL(alloc_xenballooned_pages); > @@ -630,10 +640,13 @@ EXPORT_SYMBOL(alloc_xenballooned_pages); > * @nr_pages: Number of pages > * @pages: pages to return > */ > -void free_xenballooned_pages(int nr_pages, struct page **pages) > +void free_xenballooned_pages(xenhost_t *xh, int nr_pages, struct page **pages) > { > int i; > > + if (xh->ops->free_ballooned_pages) > + return xh->ops->free_ballooned_pages(xh, nr_pages, pages); > +
Same again: please use an inline wrapper.
Juergen
| |