Hi Stefano, Wasn't this patch supposed to be folded with patch no.3 to avoid breaking the bisection?
On 25/05/2024 00:55, Stefano Stabellini wrote: > From: Henry Wang <xin.wa...@amd.com> > > There are use cases (for example using the PV driver) in Dom0less > setup that require Dom0less DomUs start immediately with Dom0, but > initialize XenStore later after Dom0's successful boot and call to > the init-dom0less application. > > An error message can seen from the init-dom0less application on > 1:1 direct-mapped domains: > ``` > Allocating magic pages > memory.c:238:d0v0 mfn 0x39000 doesn't belong to d1 > Error on alloc magic pages > ``` > > The "magic page" is a terminology used in the toolstack as reserved > pages for the VM to have access to virtual platform capabilities. > Currently the magic pages for Dom0less DomUs are populated by the > init-dom0less app through populate_physmap(), and populate_physmap() > automatically assumes gfn == mfn for 1:1 direct mapped domains. This > cannot be true for the magic pages that are allocated later from the > init-dom0less application executed in Dom0. For domain using statically > allocated memory but not 1:1 direct-mapped, similar error "failed to > retrieve a reserved page" can be seen as the reserved memory list is > empty at that time. > > Since for init-dom0less, the magic page region is only for XenStore. > To solve above issue, this commit allocates the XenStore page for > Dom0less DomUs at the domain construction time. The PFN will be > noted and communicated to the init-dom0less application executed > from Dom0. To keep the XenStore late init protocol, set the connection > status to XENSTORE_RECONNECT. > > Reported-by: Alec Kwapis <alec.kwa...@medtronic.com> > Suggested-by: Daniel P. Smith <dpsm...@apertussolutions.com> > Signed-off-by: Henry Wang <xin.wa...@amd.com> > Signed-off-by: Stefano Stabellini <stefano.stabell...@amd.com> > --- > xen/arch/arm/dom0less-build.c | 55 ++++++++++++++++++++++++++++++++++- > 1 file changed, 54 insertions(+), 1 deletion(-) > > diff --git a/xen/arch/arm/dom0less-build.c b/xen/arch/arm/dom0less-build.c > index 74f053c242..2963ecc0b3 100644 > --- a/xen/arch/arm/dom0less-build.c > +++ b/xen/arch/arm/dom0less-build.c > @@ -1,5 +1,6 @@ > /* SPDX-License-Identifier: GPL-2.0-only */ > #include <xen/device_tree.h> > +#include <xen/domain_page.h> > #include <xen/err.h> > #include <xen/event.h> > #include <xen/grant_table.h> > @@ -10,6 +11,8 @@ > #include <xen/sizes.h> > #include <xen/vmap.h> > > +#include <public/io/xs_wire.h> > + > #include <asm/arm64/sve.h> > #include <asm/dom0less-build.h> > #include <asm/domain_build.h> > @@ -739,6 +742,53 @@ static int __init alloc_xenstore_evtchn(struct domain *d) > return 0; > } > > +#define XENSTORE_PFN_OFFSET 1 > +static int __init alloc_xenstore_page(struct domain *d) > +{ > + struct page_info *xenstore_pg; > + struct xenstore_domain_interface *interface; > + mfn_t mfn; > + gfn_t gfn; > + int rc; > + > + if ( (UINT_MAX - d->max_pages) < 1 ) > + { > + printk(XENLOG_ERR "%pd: Over-allocation for d->max_pages by 1 > page.\n", > + d); > + return -EINVAL; > + } > + d->max_pages += 1; NIT: empty line here for readability > + xenstore_pg = alloc_domheap_page(d, MEMF_bits(32)); > + if ( xenstore_pg == NULL && is_64bit_domain(d) ) > + xenstore_pg = alloc_domheap_page(d, 0); > + if ( xenstore_pg == NULL ) > + return -ENOMEM; > + > + mfn = page_to_mfn(xenstore_pg); > + if ( !mfn_x(mfn) ) > + return -ENOMEM; I think you should free the allocated page here Other than that: Reviewed-by: Michal Orzel <michal.or...@amd.com> ~Michal