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Mukesh Rathor
e6390ad57b
Finally last patch in the series to enable creation of pvh dom0. A pvh dom0 is created by adding dom0pvh to grub xen command line. Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
64 lines
2.4 KiB
Plaintext
64 lines
2.4 KiB
Plaintext
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PVH : an x86 PV guest running in an HVM container.
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See: http://blog.xen.org/index.php/2012/10/23/the-paravirtualization-spectrum-part-1-the-ends-of-the-spectrum/
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At the moment HAP is required for PVH.
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At present the only PVH guest is an x86 64bit PV linux. Patches are at:
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git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git
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A PVH guest kernel must support following features, as defined for linux
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in arch/x86/xen/xen-head.S:
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#define FEATURES_PVH "|writable_descriptor_tables" \
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"|auto_translated_physmap" \
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"|supervisor_mode_kernel" \
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"|hvm_callback_vector"
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In a nutshell:
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* the guest uses auto translate:
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- p2m is managed by xen
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- pagetables are owned by the guest
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- mmu_update hypercall not available
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* it uses event callback and not vlapic emulation,
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* IDT is native, so set_trap_table hcall is also N/A for a PVH guest.
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For a full list of hcalls supported for PVH, see pvh_hypercall64_table
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in arch/x86/hvm/hvm.c in xen. From the ABI prespective, it's mostly a
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PV guest with auto translate, although it does use hvm_op for setting
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callback vector, and has a special version of arch_set_guest_info for bringing
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up secondary cpus.
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The initial phase targets the booting of a 64bit UP/SMP linux guest in PVH
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mode. This is done by adding: pvh=1 in the config file. xl, and not xm, is
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supported. Phase I patches are broken into three parts:
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- xen changes for booting of 64bit PVH guest
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- tools changes for creating a PVH guest
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- boot of 64bit dom0 in PVH mode.
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To boot 64bit dom0 in PVH mode, add dom0pvh to grub xen command line.
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Following fixme's exist in the code:
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- arch/x86/time.c: support more tsc modes.
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Following remain to be done for PVH:
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- Get rid of PVH mode, make it just HVM with some flags set
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- implement arch_get_info_guest() for pvh.
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- Investigate what else needs to be done for VMI support.
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- AMD port.
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- 32bit PVH guest support in both linux and xen. Xen changes are tagged
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"32bitfixme".
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- Add support for monitoring guest behavior. See hvm_memory_event* functions
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in hvm.c
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- vcpu hotplug support
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- Live migration of PVH guests.
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- Avail PVH dom0 of posted interrupts. (This will be a big win).
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Note, any emails to me must be cc'd to xen devel mailing list. OTOH, please
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cc me on PVH emails to the xen devel mailing list.
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Mukesh Rathor
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mukesh.rathor [at] oracle [dot] com
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