Hi Julien, > -----Original Message----- > From: Julien Grall <[email protected]> > Subject: Re: [PATCH] xen/arm: Reduce redundant clear root pages when > teardown p2m > > Hi Henry, > > > PROGRESS(p2m): > > + /* > > + * We are about to free the intermediate page-tables, so clear the > > + * root to prevent any walk to use them. > > + */ > > + p2m_clear_root_pages(&d->arch.p2m); > > The commit message suggests this should only be called once. However, > you will still end up to call p2m_clear_root_pages() multiple time if > p2m_teardown() is preempted.
Thanks for confirming this, would adding another PROGRESS stage such as PROGRESS(p2m_clean) before PROGRESS(p2m) seem ok to you? > > > ret = p2m_teardown(d, true); > > if ( ret ) > > return ret; > > diff --git a/xen/arch/arm/include/asm/p2m.h > b/xen/arch/arm/include/asm/p2m.h > > index 91df922e1c..bf5183e53a 100644 > > --- a/xen/arch/arm/include/asm/p2m.h > > +++ b/xen/arch/arm/include/asm/p2m.h > > @@ -281,6 +281,7 @@ int p2m_set_entry(struct p2m_domain *p2m, > > > > bool p2m_resolve_translation_fault(struct domain *d, gfn_t gfn); > > > > +void p2m_clear_root_pages(struct p2m_domain *p2m); > > void p2m_invalidate_root(struct p2m_domain *p2m); > > > > /* > > diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c > > index 948f199d84..0c942c5923 100644 > > --- a/xen/arch/arm/p2m.c > > +++ b/xen/arch/arm/p2m.c > > @@ -1314,6 +1314,18 @@ static void p2m_invalidate_table(struct > p2m_domain *p2m, mfn_t mfn) > > p2m->need_flush = true; > > } > > > > /* > > * The domain will not be scheduled anymore, so in theory we should > > * not need to flush the TLBs. Do it for safety purpose. > > This flush needs to be moved in p2m_clear_root_pages(). Sure, will move this in v2. Kind regards, Henry > > Cheers, > > -- > Julien Grall
