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* MIPS: KVM: Do not sign extend on unsigned MMIO loadNicholas Mc Guire2015-06-061-1/+1
| | | | | | | | | | | | | | | | Fix possible unintended sign extension in unsigned MMIO loads by casting to uint16_t in the case of mmio_needed != 2. Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Reviewed-by: James Hogan <james.hogan@imgtec.com> Tested-by: James Hogan <james.hogan@imgtec.com> Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/9985/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: KVM: Fix unused variable build warningNicholas Mc Guire2015-05-121-6/+0
| | | | | | | | | | | | | | | | | As kvm_mips_complete_mmio_load() did not yet modify PC at this point as James Hogans <james.hogan@imgtec.com> explained the curr_pc variable and the comments along with it can be dropped. Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org> Link: http://lkml.org/lkml/2015/5/8/422 Cc: Gleb Natapov <gleb@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/9993/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: KVM: Add MSA exception handlingJames Hogan2015-03-271-0/+71
| | | | | | | | | | | | | | | | | | | | | | | Add guest exception handling for MIPS SIMD Architecture (MSA) floating point exceptions and MSA disabled exceptions. MSA floating point exceptions from the guest need passing to the guest kernel, so for these a guest MSAFPE is emulated. MSA disabled exceptions are normally handled by passing a reserved instruction exception to the guest (because no guest MSA was supported), but the hypervisor can now handle them if the guest has MSA by passing an MSA disabled exception to the guest, or if the guest has MSA enabled by transparently restoring the guest MSA context and enabling MSA and the FPU. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* MIPS: KVM: Emulate MSA bits in COP0 interfaceJames Hogan2015-03-271-2/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | Emulate MSA related parts of COP0 interface so that the guest will be able to enable/disable MSA (Config5.MSAEn) once the MSA capability has been wired up. As with the FPU (Status.CU1) setting Config5.MSAEn has no immediate effect if the MSA state isn't live, as MSA state is restored lazily on first use. Changes after the MSA state has been restored take immediate effect, so that the guest can start getting MSA disabled exceptions right away for guest MSA operations. The MSA state is saved lazily too, as MSA may get re-enabled in the near future anyway. A special case is also added for when Status.CU1 is set while FR=0 and the MSA state is live. In this case we are at risk of getting reserved instruction exceptions if we try and save the MSA state, so we lose the MSA state sooner while MSA is still usable. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* MIPS: KVM: Add FP exception handlingJames Hogan2015-03-271-0/+36
| | | | | | | | | | | | | | | | | | | | | Add guest exception handling for floating point exceptions and coprocessor 1 unusable exceptions. Floating point exceptions from the guest need passing to the guest kernel, so for these a guest FPE is emulated. Also, coprocessor 1 unusable exceptions are normally passed straight through to the guest (because no guest FPU was supported), but the hypervisor can now handle them if the guest has its FPU enabled by restoring the guest FPU context and enabling the FPU. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* MIPS: KVM: Emulate FPU bits in COP0 interfaceJames Hogan2015-03-271-11/+100
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Emulate FPU related parts of COP0 interface so that the guest will be able to enable/disable the following once the FPU capability has been wired up: - The FPU (Status.CU1) - 64-bit FP register mode (Status.FR) - Hybrid FP register mode (Config5.FRE) Changing Status.CU1 has no immediate effect if the FPU state isn't live, as the FPU state is restored lazily on first use. After that, changes take place immediately in the host Status.CU1, so that the guest can start getting coprocessor unusable exceptions right away for guest FPU operations if it is disabled. The FPU state is saved lazily too, as the FPU may get re-enabled in the near future anyway. Any change to Status.FR causes the FPU state to be discarded and FPU disabled, as the register state is architecturally UNPREDICTABLE after such a change. This should also ensure that the FPU state is fully initialised (with stale state, but that's fine) when it is next used in the new FP mode. Any change to the Config5.FRE bit is immediately updated in the host state so that the guest can get the relevant exceptions right away for single-precision FPU operations. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* MIPS: KVM: Add Config4/5 and writing of Config registersJames Hogan2015-03-271-0/+52
| | | | | | | | | | | | | | | | | | | | | | | | Add Config4 and Config5 co-processor 0 registers, and add capability to write the Config1, Config3, Config4, and Config5 registers using the KVM API. Only supported bits can be written, to minimise the chances of the guest being given a configuration from e.g. QEMU that is inconsistent with that being emulated, and as such the handling is in trap_emul.c as it may need to be different for VZ. Currently the only modification permitted is to make Config4 and Config5 exist via the M bits, but other bits will be added for FPU and MSA support in future patches. Care should be taken by userland not to change bits without fully handling the possible extra state that may then exist and which the guest may begin to use and depend on. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org
* MIPS: KVM: Handle TRAP exceptions from guest kernelJames Hogan2015-03-271-0/+36
| | | | | | | | | | | | | | | | | | Trap instructions are used by Linux to implement BUG_ON(), however KVM doesn't pass trap exceptions on to the guest if they occur in guest kernel mode, instead triggering an internal error "Exception Code: 13, not yet handled". The guest kernel then doesn't get a chance to print the usual BUG message and stack trace. Implement handling of the trap exception so that it gets passed to the guest and the user is left with a more useful log message. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org
* MIPS: KVM: Handle MSA Disabled exceptions from guestJames Hogan2015-03-271-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Guest user mode can generate a guest MSA Disabled exception on an MSA capable core by simply trying to execute an MSA instruction. Since this exception is unknown to KVM it will be passed on to the guest kernel. However guest Linux kernels prior to v3.15 do not set up an exception handler for the MSA Disabled exception as they don't support any MSA capable cores. This results in a guest OS panic. Since an older processor ID may be being emulated, and MSA support is not advertised to the guest, the correct behaviour is to generate a Reserved Instruction exception in the guest kernel so it can send the guest process an illegal instruction signal (SIGILL), as would happen with a non-MSA-capable core. Fix this as minimally as reasonably possible by preventing kvm_mips_check_privilege() from relaying MSA Disabled exceptions from guest user mode to the guest kernel, and handling the MSA Disabled exception by emulating a Reserved Instruction exception in the guest, via a new handle_msa_disabled() KVM callback. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Cc: <stable@vger.kernel.org> # v3.15+
* MIPS: KVM: Remove dead code of TLB index error in kvm_mips_emul_tlbwr()Deng-Cheng Zhu2014-06-301-5/+0
| | | | | | | | | | It's impossible to fall into the error handling of the TLB index after being masked by (KVM_MIPS_GUEST_TLB_SIZE - 1). Remove the dead code. Reported-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com> Reviewed-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* MIPS: KVM: Rename files to remove the prefix "kvm_" and "kvm_mips_"Deng-Cheng Zhu2014-06-301-0/+2324
Since all the files are in arch/mips/kvm/, there's no need of the prefixes "kvm_" and "kvm_mips_". Reviewed-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>