Add support for the MIPS Virtualization (VZ) ASE to the MIPS KVM build
system. For now KVM can only be configured for T&E or VZ and not both,
but the design of the user facing APIs support the possibility of having
both available, so this could change in future.
Note that support for various optional guest features (some of which
can't be turned off) are implemented in immediately following commits,
so although it should now be possible to build VZ support, it may not
work yet on your hardware.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Implement the SYNC_MMU capability for KVM MIPS, allowing changes in the
underlying user host virtual address (HVA) mappings to be promptly
reflected in the corresponding guest physical address (GPA) mappings.
This allows for several features to work with guest RAM which require
mappings to be altered or protected, such as copy-on-write, KSM (Kernel
Samepage Merging), idle page tracking, memory swapping, and guest memory
ballooning.
There are two main aspects of this change, described below.
The KVM MMU notifier architecture callbacks are implemented so we can be
notified of changes in the HVA mappings. These arrange for the guest
physical address (GPA) page tables to be modified and possibly for
derived mappings (GVA page tables and TLBs) to be flushed.
- kvm_unmap_hva[_range]() - These deal with HVA mappings being removed,
for example before a copy-on-write takes place, which requires the
corresponding GPA page table mappings to be removed too.
- kvm_set_spte_hva() - These update a GPA page table entry to match the
new HVA entry, but must be careful to respect KVM specific
configuration such as not dirtying a clean guest page which is dirty
to the host, and write protecting writable pages in read only
memslots (which will soon be supported).
- kvm[_test]_age_hva() - These update GPA page table entries to be old
(invalid) so that access can be tracked, making them young again.
The GPA page fault handling (kvm_mips_map_page) is updated to use
gfn_to_pfn_prot() (which may provide read-only pages), to handle
asynchronous page table invalidation from MMU notifier callbacks, and to
handle more cases in the fast path.
- mmu_notifier_seq is used to detect asynchronous page table
invalidations while we're holding a pfn from gfn_to_pfn_prot()
outside of kvm->mmu_lock, retrying if invalidations have taken place,
e.g. a COW or a KSM page merge.
- The fast path (_kvm_mips_map_page_fast) now handles marking old pages
as young / accessed, and disallowing dirtying of clean pages that
aren't actually writable (e.g. shared pages that should COW, and
read-only memory regions when they are enabled in a future patch).
- Due to the use of MMU notifications we no longer need to keep the
page references after we've updated the GPA page tables.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
MIPS hasn't up to this point properly supported dirty page logging, as
pages in slots with dirty logging enabled aren't made clean, and tlbmod
exceptions from writes to clean pages have been assumed to be due to
guest TLB protection and unconditionally passed to the guest.
Use the generic dirty logging helper kvm_get_dirty_log_protect() to
properly implement kvm_vm_ioctl_get_dirty_log(), similar to how ARM
does. This uses xchg to clear the dirty bits when reading them, rather
than wiping them out afterwards with a memset, which would potentially
wipe recently set bits that weren't caught by kvm_get_dirty_log(). It
also makes the pages clean again using the
kvm_arch_mmu_enable_log_dirty_pt_masked() architecture callback so that
further writes after the shadow memslot is flushed will trigger tlbmod
exceptions and dirty handling.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Convert the whole of locore.S (assembly to enter guest and handle
exception entry) to be generated dynamically with uasm. This is done
with minimal changes to the resulting code.
The main changes are:
- Some constants are generated by uasm using LUI+ADDIU instead of
LUI+ORI.
- Loading of lo and hi are swapped around in vcpu_run but not when
resuming the guest after an exit. Both bits of logic are now generated
by the same code.
- Register MOVEs in uasm use different ADDU operand ordering to GNU as,
putting zero register into rs instead of rt.
- The JALR.HB to call the C exit handler is switched to JALR, since the
hazard barrier would appear to be unnecessary.
This will allow further optimisation in the future to dynamically handle
the capabilities of the CPU.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim KrÄmář <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
SRCU is not necessary to be compiled by default in all cases. For tinification
efforts not compiling SRCU unless necessary is desirable.
The current patch tries to make compiling SRCU optional by introducing a new
Kconfig option CONFIG_SRCU which is selected when any of the components making
use of SRCU are selected.
If we do not select CONFIG_SRCU, srcu.o will not be compiled at all.
text data bss dec hex filename
2007 0 0 2007 7d7 kernel/rcu/srcu.o
Size of arch/powerpc/boot/zImage changes from
text data bss dec hex filename
831552 64180 23944 919676 e087c arch/powerpc/boot/zImage : before
829504 64180 23952 917636 e0084 arch/powerpc/boot/zImage : after
so the savings are about ~2000 bytes.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: resolve conflict due to removal of arch/ia64/kvm/Kconfig. ]
Virtualization does not always need KVM capabilities so drop the
dependency. The KVM symbol already depends on HAVE_KVM.
Fixes the following problem on a randconfig:
warning: (REMOTEPROC && RPMSG) selects VIRTUALIZATION which has unmet direct
dependencies (HAVE_KVM)
warning: (REMOTEPROC && RPMSG) selects VIRTUALIZATION which has unmet
direct dependencies (HAVE_KVM)
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Acked-by: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5443/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
- Add the KVM option to MIPS build files.
- Add default config files for KVM host/guest kernels.
- Change the link address for the Malta KVM Guest kernel to UM (0x40100000).
- Add KVM Kconfig file with KVM/MIPS specific options
Signed-off-by: Sanjay Lal <sanjayl@kymasys.com>
Cc: kvm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
James Hogan