There exists a slightly dubious optimisation in the implementation of
the MIPS KVM EntryHi emulation which skips TLB invalidation if the
EntryHi points to an address in the guest KSeg0 region, intended to
catch guest TLB invalidations where the ASID is almost immediately
restored to the previous value.
Now that we perform lazy host ASID regeneration for guest user mode when
the guest ASID changes we should be able to drop the optimisation
without a significant impact (only the extra TLB refills for the small
amount of code while the TLB is being invalidated).
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
Invalidate host TLB mappings when the guest ASID is changed by
regenerating ASIDs, rather than flushing the entire host TLB except
entries in the guest KSeg0 range.
For the guest kernel mode ASID we regenerate on the spot when the guest
ASID is changed, as that will always take place while the guest is in
kernel mode.
However when the guest invalidates TLB entries the ASID will often by
changed temporarily as part of writing EntryHi without the guest
returning to user mode in between. We therefore regenerate the user mode
ASID lazily before entering the guest in user mode, if and only if the
guest ASID has actually changed since the last guest user mode entry.
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
The host ASIDs for guest kernel and user mode are regenerated together
if the ASID for guest kernel mode is out of date. That is fine as the
ASID for guest kernel mode is always generated first, however it doesn't
allow the ASIDs to be regenerated or invalidated individually instead of
linearly flushing the entire host TLB.
Therefore separate the regeneration code so that the ASIDs are checked
and regenerated separately.
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
When a guest TLB entry is replaced by TLBWI or TLBWR, we only invalidate
TLB entries on the local CPU. This doesn't work correctly on an SMP host
when the guest is migrated to a different physical CPU, as it could pick
up stale TLB mappings from the last time the vCPU ran on that physical
CPU.
Therefore invalidate both user and kernel host ASIDs on other CPUs,
which will cause new ASIDs to be generated when it next runs on those
CPUs.
We're careful only to do this if the TLB entry was already valid, and
only for the kernel ASID where the virtual address it mapped is outside
of the guest user address range.
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
Cc: <stable@vger.kernel.org> # 3.10.x-
Two stubs are added:
o kvm_arch_has_vcpu_debugfs(): must return true if the arch
supports creating debugfs entries in the vcpu debugfs dir
(which will be implemented by the next commit)
o kvm_arch_create_vcpu_debugfs(): code that creates debugfs
entries in the vcpu debugfs dir
For x86, this commit introduces a new file to avoid growing
arch/x86/kvm/x86.c even more.
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
MIPS Enhanced Virtual Addressing (EVA) allows the virtual memory
segments to be rearranged such that the KSeg0/KSeg1 segments are
accessible TLB mapped to user mode, which would trigger a TLB Miss
exception (due to lack of TLB mappings) instead of an Address Error
exception.
Update the TLB Miss handling similar to Address Error handling for guest
MMIO emulation.
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
When mapping a page into the guest we error check using is_error_pfn(),
however this doesn't detect a value of KVM_PFN_NOSLOT, indicating an
error HVA for the page. This can only happen on MIPS right now due to
unusual memslot management (e.g. being moved / removed / resized), or
with an Enhanced Virtual Memory (EVA) configuration where the default
KVM_HVA_ERR_* and kvm_is_error_hva() definitions are unsuitable (fixed
in a later patch). This case will be treated as a pfn of zero, mapping
the first page of physical memory into the guest.
It would appear the MIPS KVM port wasn't updated prior to being merged
(in v3.10) to take commit 81c52c56e2 ("KVM: do not treat noslot pfn as
a error pfn") into account (merged v3.8), which converted a bunch of
is_error_pfn() calls to is_error_noslot_pfn(). Switch to using
is_error_noslot_pfn() instead to catch this case properly.
Fixes: 858dd5d457 ("KVM/MIPS32: MMU/TLB operations for the Guest.")
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
Cc: <stable@vger.kernel.org> # 3.10.y-
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Propagate errors from kvm_mips_handle_kseg0_tlb_fault() and
kvm_mips_handle_mapped_seg_tlb_fault(), usually triggering an internal
error since they normally indicate the guest accessed bad physical
memory or the commpage in an unexpected way.
Fixes: 858dd5d457 ("KVM/MIPS32: MMU/TLB operations for the Guest.")
Fixes: e685c689f3 ("KVM/MIPS32: Privileged instruction/target branch emulation.")
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
Cc: <stable@vger.kernel.org> # 3.10.x-
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Two consecutive gfns are loaded into host TLB, so ensure the range check
isn't off by one if guest_pmap_npages is odd.
Fixes: 858dd5d457 ("KVM/MIPS32: MMU/TLB operations for the Guest.")
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
Cc: <stable@vger.kernel.org> # 3.10.x-
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
kvm_mips_handle_mapped_seg_tlb_fault() calculates the guest frame number
based on the guest TLB EntryLo values, however it is not range checked
to ensure it lies within the guest_pmap. If the physical memory the
guest refers to is out of range then dump the guest TLB and emit an
internal error.
Fixes: 858dd5d457 ("KVM/MIPS32: MMU/TLB operations for the Guest.")
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
Cc: <stable@vger.kernel.org> # 3.10.x-
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
kvm_mips_handle_mapped_seg_tlb_fault() appears to map the guest page at
virtual address 0 to PFN 0 if the guest has created its own mapping
there. The intention is unclear, but it may have been an attempt to
protect the zero page from being mapped to anything but the comm page in
code paths you wouldn't expect from genuine commpage accesses (guest
kernel mode cache instructions on that address, hitting trapping
instructions when executing from that address with a coincidental TLB
eviction during the KVM handling, and guest user mode accesses to that
address).
Fix this to check for mappings exactly at KVM_GUEST_COMMPAGE_ADDR (it
may not be at address 0 since commit 42aa12e74e ("MIPS: KVM: Move
commpage so 0x0 is unmapped")), and set the corresponding EntryLo to be
interpreted as 0 (invalid).
Fixes: 858dd5d457 ("KVM/MIPS32: MMU/TLB operations for the Guest.")
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
Cc: <stable@vger.kernel.org> # 3.10.x-
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
KVM sometimes flushes host TLB entries, reading each one to check if it
corresponds to a guest KSeg0 address. In the absence of EntryHi.EHInv
bits to invalidate the whole entry, the entries will be set to unique
virtual addresses in KSeg0 (which is not TLB mapped), spaced 2*PAGE_SIZE
apart.
The TLB read however will clobber the CP0_PageMask register with
whatever page size that TLB entry had, and that same page size will be
written back into the TLB entry along with the unique address.
This would cause breakage when transparent huge pages are enabled on
64-bit host kernels, since huge page entries will overlap other nearby
entries when separated by only 2*PAGE_SIZE, causing a machine check
exception.
Fix this by restoring the old CP0_PageMask value (which should be set to
the normal page size) after reading the TLB entry if we're going to go
ahead and invalidate it.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm_mips_trans_replace() passes a pointer to KVM_GUEST_KSEGX(). This
breaks on 64-bit builds due to the cast of that 64-bit pointer to a
different sized 32-bit int. Cast the pointer argument to an unsigned
long to work around the warning.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When emulating MFC0 instructions to load 32-bit values from guest COP0
registers and the RDHWR instruction to read the CC (Count) register,
sign extend the result to comply with the MIPS64 architecture. The
result must be in canonical 32-bit form or the guest may malfunction.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The MFC0 and MTC0 instructions in the guest which cause traps can be
replaced with 32-bit loads and stores to the commpage, however on big
endian 64-bit builds the offset needs to have 4 added so as to
load/store the least significant half of the long instead of the most
significant half.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Fail if the address of the allocated exception base doesn't fit into the
CP0_EBase register. This can happen on MIPS64 if CP0_EBase.WG isn't
implemented but RAM is available outside of the range of KSeg0.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Update the KVM entry point to write CP0_EBase as a 64-bit register when
it is 64-bits wide, and to set the WG (write gate) bit if it exists in
order to write bits 63:30 (or 31:30 on MIPS32).
Prior to MIPS64r6 it was UNDEFINED to perform a 64-bit read or write of
a 32-bit COP0 register. Since this is dynamically generated code,
generate the right type of access depending on whether the kernel is
64-bit and cpu_has_ebase_wg.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Update the KVM entry code to set the CP0_Entry.KX bit on 64-bit kernels.
This is important to allow the entry code, running in kernel mode, to
access the full 64-bit address space right up to the point of entering
the guest, and immediately after exiting the guest, so it can safely
restore & save the guest context from 64-bit segments.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The MIPS KVM entry code (originally kvm_locore.S, later locore.S, and
now entry.c) has never quite been right when built for 64-bit, using
32-bit instructions when 64-bit instructions were needed for handling
64-bit registers and pointers. Fix several cases of this now.
The changes roughly fall into the following categories.
- COP0 scratch registers contain guest register values and the VCPU
pointer, and are themselves full width. Similarly CP0_EPC and
CP0_BadVAddr registers are full width (even though technically we
don't support 64-bit guest address spaces with trap & emulate KVM).
Use MFC0/MTC0 for accessing them.
- Handling of stack pointers and the VCPU pointer must match the pointer
size of the kernel ABI (always o32 or n64), so use ADDIU.
- The CPU number in thread_info, and the guest_{user,kernel}_asid arrays
in kvm_vcpu_arch are all 32 bit integers, so use lw (instead of LW) to
load them.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
There are several unportable uses of CKSEG0ADDR() in MIPS KVM, which
implicitly assume that a host physical address will be in the low 512MB
of the physical address space (accessible in KSeg0). These assumptions
don't hold for highmem or on 64-bit kernels.
When interpreting the guest physical address when reading or overwriting
a trapping instruction, use kmap_atomic() to get a usable virtual
address to access guest memory, which is portable to 64-bit and highmem
kernels.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Calculate the PFN of the commpage using virt_to_phys() instead of
CPHYSADDR(). This is more portable as kzalloc() may allocate from XKPhys
instead of KSeg0 on 64-bit kernels, which CPHYSADDR() doesn't handle.
This is sufficient for highmem kernels too since kzalloc() will allocate
from lowmem in KSeg0.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Default the guest PRId register to represent a generic QEMU machine
instead of a 24kc on MIPSr6. 24kc isn't supported by r6 Linux kernels.
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>
When KVM emulates the RDHWR instruction, decode the instruction more
strictly. The rs field (bits 25:21) should be zero, as should bits 10:9.
Bits 8:6 is the register select field in MIPSr6, so we aren't strict
about those bits (no other operations should use that encoding space).
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>
Recognise the new MIPSr6 CACHE instruction encoding rather than the
pre-r6 one when an r6 kernel is being built. A SPECIAL3 opcode is used
and the immediate field is reduced to 9 bits wide since MIPSr6.
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>
Add support in KVM for emulation of instructions in the forbidden slot
of MIPSr6 compact branches. If we hit an exception on the forbidden
slot, then the branch must not have been taken, which makes calculation
of the resume PC trivial.
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>
MIPSr6 doesn't have lo/hi registers, so don't bother saving or
restoring them, and don't expose them to userland with the KVM ioctl
interface either.
In fact the lo/hi registers aren't callee saved in the MIPS ABIs anyway,
so there is no need to preserve the host lo/hi values at all when
transitioning to and from the guest (which happens via a function call).
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>
__kvm_save_fpu and __kvm_restore_fpu use .set mips64r2 so that they can
access the odd FPU registers as well as the even, however this causes
misassembly of the return instruction on MIPSr6.
Fix by replacing .set mips64r2 with .set fp=64, which doesn't change the
architecture revision.
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>
Currently on a guest exception the guest's k0 register is saved to the
scratch temp register and the guest k1 saved to the exception base
address + 0x3000 using k0 to extract the Exception Base field of the
EBase register and as the base operand to the store. Both are then
copied into the VCPU structure after the other general purpose registers
have been saved there.
This bouncing to exception base + 0x3000 is not actually necessary as
the VCPU pointer can be determined and written through just as easily
with only a single spare register. The VCPU pointer is already needed in
k1 for saving the other GP registers, so lets save the guest k0 register
straight into the VCPU structure through k1, first saving k1 into the
scratch temp register instead of k0.
This could potentially pave the way for having a single exception base
area for use by all guests.
The ehb after saving the k register to the scratch temp register is also
delayed until just before it needs to be read back.
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>
Use a relative branch to get from the individual exception vectors to
the common guest exit handler, rather than loading the address of the
exit handler and jumping to it.
This is made easier due to the fact we are now generating the entry code
dynamically. This will also allow the exception code to be further
reduced in future patches.
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>
Scratch cop0 registers are needed by KVM to be able to save/restore all
the GPRs, including k0/k1, and for storing the VCPU pointer. However no
registers are universally suitable for these purposes, so the decision
should be made at runtime.
Until now, we've used DDATA_LO to store the VCPU pointer, and ErrorEPC
as a temporary. It could be argued that this is abuse of those
registers, and DDATA_LO is known not to be usable on certain
implementations (Cavium Octeon). If KScratch registers are present, use
them instead.
We save & restore the temporary register in addition to the VCPU pointer
register when using a KScratch register for it, as it may be used for
normal host TLB handling too.
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>
On return from the exit handler to the host (without re-entering the
guest) we restore the saved value of the DDATA_LO register which we use
as a scratch register. However we've already restored it ready for
calling the exit handler so there is no need to do it again, so drop
that code.
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>
Check for presence of MSA at uasm assembly time rather than at runtime
in the generated KVM host entry code. This optimises the guest exit path
by eliminating the MSA code entirely if not present, and eliminating the
read of Config3.MSAP and conditional branch if MSA is present.
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>
The FPU handling code on entry from guest is unnecessary if no FPU is
present, so allow it to be dropped at uasm assembly time.
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>
Dump the generated entry code with pr_debug(), similar to how it is done
in tlbex.c, so it can be more easily debugged.
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>
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>
Use the functions from context_tracking.h directly.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Combine the kvm_enter, kvm_reenter and kvm_out trace events into a
single kvm_transition event class to reduce duplication and bloat.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Fixes: 93258604ab ("MIPS: KVM: Add guest mode switch trace events")
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: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Convert MIPS KVM guest register state initialisation to use the standard
<asm/mipsregs.h> register field definitions for Config registers, and
drop the custom definitions in kvm_host.h which it was using before.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Initialise the guest's CP0_Config register with a few more bits of
information from the host. The BE bit should be set on big endian
machines, the VI bit should be set on machines with a virtually tagged
instruction cache, and the reported architecture revision should match
that of the host (since we won't support emulating pre-r6 instruction
encodings on r6 or vice versa).
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM TLB mappings for the guest were being created with a cache coherency
attribute (CCA) of 3, which is cached incoherent. Create them instead
with the default host CCA, which should be the correct one for coherency
on SMP systems.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The comm page which is mapped into the guest kernel address space at
0x0 has the unfortunate side effect of allowing guest kernel NULL
pointer dereferences to succeed. The only constraint on this address is
that it must be within 32KiB of 0x0, so that single lw/sw instructions
(which have 16-bit signed offset fields) can be used to access it, using
the zero register as a base.
So lets move the comm page as high as possible within that constraint so
that 0x0 can be left unmapped, at least for page sizes < 32KiB.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Allow up to 6 KVM guest KScratch registers to be enabled and accessed
via the KVM guest register API and from the guest itself (the fallback
reading and writing of commpage registers is sufficient for KScratch
registers to work as expected).
User mode can expose the registers by setting the appropriate bits of
the guest Config4.KScrExist field. KScratch registers that aren't usable
won't be writeable via the KVM Ioctl API.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Actually provide the VCPU number when emulating the RDHWR CPUNum
register, so that it will match the CPUNum field of CP0_EBase register,
rather than always returning 0.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The ULRI bit in Config3 specifies whether the UserLocal register is
implemented, but it is assumed to always be set. Now that the Config
registers can be modified by userland, allow Config3.ULRI to be cleared
and check ULRI before allowing the corresponding bit to be set in
HWREna.
In fact any HWREna bits corresponding to unimplemented RDHWR registers
should read as zero and be ignored on write, so we actually prevent
other unimplemented bits being set too.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM modifies CP0_HWREna during guest execution so it can trap and
emulate RDHWR instructions, however it always restores the hardcoded
value 0x2000000F. This assumes the presence of the UserLocal register,
and the absence of any implementation dependent or future HW registers.
Fix by exporting the value that traps.c write into CP0_HWREna, and
loading from there instead of hard coding.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
No preprocessor definitions are used in the handling of the registers
accessible with the RDHWR instruction, nor the corresponding bits in the
CP0 HWREna register.
Add definitions for both the register numbers (MIPS_HWR_*) and HWREna
bits (MIPS_HWRENA_*) in asm/mipsregs.h and make use of them in the
initialisation of HWREna and emulation of the RDHWR instruction.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Make KVM_GET_REG_LIST list FPU & MSA registers. Specifically we list all
32 vector registers when MSA can be enabled, 32 single-precision FP
registers when FPU can be enabled, and either 16 or 32 double-precision
FP registers when FPU can be enabled depending on whether FR mode is
supported (which provides 32 doubles instead of 16 even doubles).
Note, these registers may still be inaccessible depending on the current
FP mode of the guest.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Make the implementation of KVM_GET_REG_LIST more dynamic so that only
the subset of registers actually available can be exposed to user mode.
This is important for VZ where some of the guest register state may not
be possible to prevent the guest from accessing, therefore the user
process may need to be aware of the state even if it doesn't understand
what the state is for.
This also allows different MIPS KVM implementations to provide different
registers to one another, by way of new num_regs(vcpu) and
copy_reg_indices(vcpu, indices) callback functions, currently just
stubbed for trap & emulate.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pass all unrecognised register IDs through to the set_one_reg() and
get_one_reg() callbacks, not just select ones. This allows
implementation specific registers to be more easily added without having
to modify arch/mips/kvm/mips.c.
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
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
