kernel/linux.git/arch/mips/kvm/emulate.c, branch linux-4.16.y

KVM: add kvm_{test,clear}_request to replace {test,clear}_bit

2017-04-27T12:12:22+00:00

Users were expected to use kvm_check_request() for testing and clearing, but request have expanded their use since then and some users want to only test or do a faster clear. Make sure that requests are not directly accessed with bit operations. Reviewed-by: Christian Borntraeger Signed-off-by: Radim Krčmář Reviewed-by: Andrew Jones Reviewed-by: Cornelia Huck Signed-off-by: Paolo Bonzini

KVM: MIPS/Emulate: Properly implement TLBR for T&E

2017-03-28T15:31:37+00:00

Properly implement emulation of the TLBR instruction for Trap & Emulate. This instruction reads the TLB entry pointed at by the CP0_Index register into the other TLB registers, which may have the side effect of changing the current ASID. Therefore abstract the CP0_EntryHi and ASID changing code into a common function in the process. A comment indicated that Linux doesn't use TLBR, which is true during normal use, however dumping of the TLB does use it (for example with the relatively recent 'x' magic sysrq key), as does a wired TLB entries test case in my KVM tests. Signed-off-by: James Hogan Acked-by: Ralf Baechle Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: Adapt T&E CACHE emulation for Octeon

2017-03-28T14:36:17+00:00

Cache management is implemented separately for Cavium Octeon CPUs, so r4k_blast_[id]cache aren't available. Instead for Octeon perform a local icache flush using local_flush_icache_range(), and for other platforms which don't use c-r4k.c use __flush_cache_all() / flush_icache_all(). Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: David Daney Cc: Andreas Herrmann Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org

KVM: MIPS/VZ: Support hardware guest timer

2017-03-28T13:53:59+00:00

Transfer timer state to the VZ guest context (CP0_GTOffset & guest CP0_Count) when entering guest mode, enabling direct guest access to it, and transfer back to soft timer when saving guest register state. This usually allows guest code to directly read CP0_Count (via MFC0 and RDHWR) and read/write CP0_Compare, without trapping to the hypervisor for it to emulate the guest timer. Writing to CP0_Count or CP0_Cause.DC is much less common and still triggers a hypervisor GPSI exception, in which case the timer state is transferred back to an hrtimer before emulating the write. We are careful to prevent small amounts of drift from building up due to undeterministic time intervals between reading of the ktime and reading of CP0_Count. Some drift is expected however, since the system clocksource may use a different timer to the local CP0_Count timer used by VZ. This is permitted to prevent guest CP0_Count from appearing to go backwards. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: Drop CACHE emulation for VZ

2017-03-28T13:53:53+00:00

Ifdef out the trap & emulate CACHE instruction emulation functions for VZ. We will provide separate CACHE instruction emulation in vz.c, and we need to avoid linker errors due to the use of T&E specific MMU helpers. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: Update CP0_Compare emulation for VZ

2017-03-28T13:53:52+00:00

Update emulation of guest writes to CP0_Compare for VZ. There are two main differences compared to trap & emulate: - Writing to CP0_Compare in the VZ hardware guest context acks any pending timer, clearing CP0_Cause.TI. If we don't want an ack to take place we must carefully restore the TI bit if it was previously set. - Even with guest timer access disabled in CP0_GuestCtl0.GT, if the guest CP0_Count reaches the guest CP0_Compare the timer interrupt will assert. To prevent this we must set CP0_GTOffset to move the guest CP0_Count out of the way of the new guest CP0_Compare, either before or after depending on whether it is a forwards or backwards change. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org

KVM: MIPS: Abstract guest CP0 register access for VZ

2017-03-28T13:53:50+00:00

Abstract the MIPS KVM guest CP0 register access macros into inline functions which are generated by macros. This allows them to be generated differently for VZ, where they will usually need to access the hardware guest CP0 context rather than the saved values in RAM. Accessors for each individual register are generated using these macros: - __BUILD_KVM_*_SW() for registers which are not present in the VZ hardware guest context, so kvm_{read,write}_c0_guest_##name() will access the saved value in RAM regardless of whether VZ is enabled. - __BUILD_KVM_*_HW() for registers which are present in the VZ hardware guest context, so kvm_{read,write}_c0_guest_##name() will access the hardware register when VZ is enabled. These build the underlying accessors using further macros: - __BUILD_KVM_*_SAVED() builds e.g. kvm_{read,write}_sw_gc0_##name() functions for accessing the saved versions of the registers in RAM. This is used for implementing the common kvm_{read,write}_c0_guest_##name() accessors with T&E where registers are always stored in RAM, but are also available with VZ HW registers to allow them to be accessed while saved. - __BUILD_KVM_*_VZ() builds e.g. kvm_{read,write}_vz_gc0_##name() functions for accessing the VZ hardware guest context registers directly. This is used for implementing the common kvm_{read,write}_c0_guest_##name() accessors with VZ. - __BUILD_KVM_*_WRAP() builds wrappers with different names, which allows the common kvm_{read,write}_c0_guest_##name() functions to be implemented using the VZ accessors while still having the SAVED accessors available too. - __BUILD_KVM_SAVE_VZ() builds functions for saving and restoring VZ hardware guest context register state to RAM, improving conciseness of VZ context saving and restoring. Similar macros exist for generating modifiers (set, clear, change), either with a normal unlocked read/modify/write, or using atomic LL/SC sequences. These changes change the types of 32-bit registers to u32 instead of unsigned long, which requires some changes to printk() functions in MIPS KVM. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org

KVM: MIPS: Init timer frequency from callback

2017-03-28T13:53:48+00:00

Currently the software emulated timer is initialised to a frequency of 100MHz by kvm_mips_init_count(), but this isn't suitable for VZ where the frequency of the guest timer matches that of the host. Add a count_hz argument so the caller can specify the default frequency, and move the call from kvm_arch_vcpu_create() to the implementation specific vcpu_setup() callback, so that VZ can specify a different frequency. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: Implement 64-bit MMIO emulation

2017-03-28T13:53:45+00:00

Implement additional MMIO emulation for MIPS64, including 64-bit loads/stores, and 32-bit unsigned loads. These are only exposed on 64-bit VZ hosts. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org

KVM: MIPS/Emulate: De-duplicate MMIO emulation

2017-03-28T13:53:44+00:00

Refactor MIPS KVM MMIO load/store emulation to reduce code duplication. Each duplicate differed slightly anyway, and it will simplify adding 64-bit MMIO support for VZ. kvm_mips_emulate_store() and kvm_mips_emulate_load() can now return EMULATE_DO_MMIO (as possibly originally intended). We therefore stop calling either of these from kvm_mips_emulate_inst(), which is now only used by kvm_trap_emul_handle_cop_unusable() which is picky about return values. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org