Messages in this thread | | | Subject | Re: [Xen-devel] [PATCH 2/2] xen: add sysfs node for guest type | From | Andrew Cooper <> | Date | Mon, 22 May 2017 14:33:20 +0100 |
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On 22/05/17 09:57, Juergen Gross wrote: > Currently there is no reliable user interface inside a Xen guest to > determine its type (e.g. HVM, PV or PVH). Instead of letting user mode > try to determine this by various rather hacky mechanisms (parsing of > boot messages before they are gone, trying to make use of known subtle > differences in behavior of some instructions), add a sysfs node > /sys/hypervisor/guest_type to explicitly deliver this information as > it is known to the kernel. > > Signed-off-by: Juergen Gross <jgross@suse.com> > --- > Documentation/ABI/testing/sysfs-hypervisor | 13 +++++++++++++ > arch/arm/xen/enlighten.c | 3 +++ > arch/x86/xen/enlighten.c | 3 +++ > arch/x86/xen/enlighten_hvm.c | 6 ++++-- > arch/x86/xen/enlighten_pv.c | 1 + > drivers/xen/sys-hypervisor.c | 17 +++++++++++++++++ > include/xen/xen.h | 2 ++ > 7 files changed, 43 insertions(+), 2 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-hypervisor b/Documentation/ABI/testing/sysfs-hypervisor > index 443196f0aa1c..06850f74ebd4 100644 > --- a/Documentation/ABI/testing/sysfs-hypervisor > +++ b/Documentation/ABI/testing/sysfs-hypervisor > @@ -19,6 +19,19 @@ Contact: xen-devel@lists.xenproject.org > Description: > Compiler which was used to build the Xen hypervisor > > +What: /sys/hypervisor/guest_type > +Date: May 2017 > +KernelVersion: 4.12 > +Contact: xen-devel@lists.xenproject.org > +Description: > + Type of guest: > + "native": standard guest type on arm > + "HVM": fully virtualized guest (x86) > + "PV": paravirtualized guest (x86) > + "PVH": fully virtualized guest without legacy emulation (x86) > + "PVHVM": fully virtualized guest using paravirtualized > + interfaces (e.g. interrupts, timers) (x86)
I'm not sure this is wise split. PVHVM is a spectrum which changes dynamically, especially in the presence of hardware APIC support.
I'd suggest guest type being straight PV or HVM (being the container type), and a list of items (interrupts, timers, legacy emulation) which are either using paravirt or native interfaces, or are not used at all.
~Andrew
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