Messages in this thread | | | Subject | Re: [PATCH v2 5/7] x86/xen: nopv parameter support for HVM guest | From | Juergen Gross <> | Date | Tue, 25 Jun 2019 14:31:05 +0200 |
| |
On 24.06.19 14:02, Zhenzhong Duan wrote: > PVH guest needs PV extentions to work, so nopv parameter is ignored > for PVH but not for HVM guest. > > In order for nopv parameter to take effect for HVM guest, we need to > distinguish between PVH and HVM guest early in hypervisor detection > code. By moving the detection of PVH in xen_platform_hvm(), > xen_pvh_domain() could be used for that purpose. > > Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com> > Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> > Cc: Juergen Gross <jgross@suse.com> > Cc: Stefano Stabellini <sstabellini@kernel.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Borislav Petkov <bp@alien8.de> > Cc: xen-devel@lists.xenproject.org > --- > arch/x86/xen/enlighten_hvm.c | 18 ++++++++++++------ > 1 file changed, 12 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c > index 7fcb4ea..26939e7 100644 > --- a/arch/x86/xen/enlighten_hvm.c > +++ b/arch/x86/xen/enlighten_hvm.c > @@ -25,6 +25,7 @@ > #include "mmu.h" > #include "smp.h" > > +extern bool nopv; > static unsigned long shared_info_pfn; > > void xen_hvm_init_shared_info(void) > @@ -226,20 +227,24 @@ static uint32_t __init xen_platform_hvm(void) > if (xen_pv_domain()) > return 0; > > +#ifdef CONFIG_XEN_PVH > + /* Test for PVH domain (PVH boot path taken overrides ACPI flags). */ > + if (!x86_platform.legacy.rtc && x86_platform.legacy.no_vga) > + xen_pvh = true;
Sorry, this won't work, as ACPI tables are scanned only some time later.
You can test for xen_pvh being true here (for the case where the guest has been booted via the Xen-PVH boot entry) and handle that case, but the case of a PVH guest started via the normal boot entry (like via grub2) and nopv specified is difficult. The only idea I have right now would be to use another struct hypervisor_x86 for that case which will only be used for Xen HVM/PVH _and_ nopv specified. It should be a copy of the bare metal variant, but a special guest_late_init member issuing a big fat warning in case PVH is being detected.
Juergen
| |