kernel/arch/powerpc/include/asm/kvm_book3s_asm.h, branch linux-6.2.y

powerpc/kvm: Remove unused references for MMCR3/SIER2/SIER3 registers

2022-11-24T12:31:47Z

Commit 57dc0eed73ca ("KVM: PPC: Book3S HV P9: Implement PMU save/restore in C") removed the PMU save/restore functions from assembly code and implemented these functions in C, for power9 and later platforms. After the code refactoring, Performance Monitoring Unit (PMU) registers became part of "p9_host_os_sprs" structure and now this structure is used to save/restore pmu host registers, for power9 and later platfroms. But we still have old unused registers references. Patch removes unused host_mmcr references for Monitor Mode Control Register 3 (MMCR3)/ Sampled Instruction Event Register 2 (SIER2)/ SIER3 registers from "struct kvmppc_host_state". Fixes: 57dc0eed73ca ("KVM: PPC: Book3S HV P9: Implement PMU save/restore in C") Signed-off-by: Kajol Jain Reviewed-by: Nicholas Piggin Reviewed-by: Athira Rajeev Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220916105736.268153-3-disgoel@linux.vnet.ibm.com

KVM: PPC: Book3S HV: Remove KVMPPC_NR_LPIDS

2022-05-13T11:33:34Z

KVMPPC_NR_LPIDS no longer represents any size restriction on the LPID space and can be removed. A CPU with more than 12 LPID bits implemented will now be able to create more than 4095 guests. Signed-off-by: Nicholas Piggin Reviewed-by: Fabiano Rosas Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220123120043.3586018-7-npiggin@gmail.com

KVM: PPC: Book3S HV: Update LPID allocator init for POWER9, Nested

2022-05-13T11:33:33Z

The LPID allocator init is changed to: - use mmu_lpid_bits rather than hard-coding; - use KVM_MAX_NESTED_GUESTS for nested hypervisors; - not reserve the top LPID on POWER9 and newer CPUs. The reserved LPID is made a POWER7/8-specific detail. Signed-off-by: Nicholas Piggin Reviewed-by: Fabiano Rosas Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220123120043.3586018-3-npiggin@gmail.com

KVM: PPC: Book3S HV: Remove support for running HPT guest on RPT host without mixed mode support

2021-02-10T03:31:08Z

This reverts much of commit c01015091a770 ("KVM: PPC: Book3S HV: Run HPT guests on POWER9 radix hosts"), which was required to run HPT guests on RPT hosts on early POWER9 CPUs without support for "mixed mode", which meant the host could not run with MMU on while guests were running. This code has some corner case bugs, e.g., when the guest hits a machine check or HMI the primary locks up waiting for secondaries to switch LPCR to host, which they never do. This could all be fixed in software, but most CPUs in production have mixed mode support, and those that don't are believed to be all in installations that don't use this capability. So simplify things and remove support. Signed-off-by: Nicholas Piggin Tested-by: Fabiano Rosas Signed-off-by: Paul Mackerras

KVM: PPC: Book3S HV: Save/restore new PMU registers

2020-07-22T11:56:41Z

Power ISA v3.1 has added new performance monitoring unit (PMU) special purpose registers (SPRs). They are: Monitor Mode Control Register 3 (MMCR3) Sampled Instruction Event Register A (SIER2) Sampled Instruction Event Register B (SIER3) Add support to save/restore these new SPRs while entering/exiting guest. Also include changes to support KVM_REG_PPC_MMCR3/SIER2/SIER3. Add new SPRs to KVM API documentation. Signed-off-by: Athira Rajeev Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1594996707-3727-6-git-send-email-atrajeev@linux.vnet.ibm.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 266

2019-06-05T15:30:28Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation 51 franklin street fifth floor boston ma 02110 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 67 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Reviewed-by: Alexios Zavras Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141333.953658117@linutronix.de Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Book3S HV: Framework and hcall stubs for nested virtualization

2018-10-09T05:04:27Z

This starts the process of adding the code to support nested HV-style virtualization. It defines a new H_SET_PARTITION_TABLE hypercall which a nested hypervisor can use to set the base address and size of a partition table in its memory (analogous to the PTCR register). On the host (level 0 hypervisor) side, the H_SET_PARTITION_TABLE hypercall from the guest is handled by code that saves the virtual PTCR value for the guest. This also adds code for creating and destroying nested guests and for reading the partition table entry for a nested guest from L1 memory. Each nested guest has its own shadow LPID value, different in general from the LPID value used by the nested hypervisor to refer to it. The shadow LPID value is allocated at nested guest creation time. Nested hypervisor functionality is only available for a radix guest, which therefore means a radix host on a POWER9 (or later) processor. Signed-off-by: Paul Mackerras Reviewed-by: David Gibson Signed-off-by: Michael Ellerman

KVM: PPC: Book3S HV: Work around transactional memory bugs in POWER9

2018-03-23T13:39:13Z

POWER9 has hardware bugs relating to transactional memory and thread reconfiguration (changes to hardware SMT mode). Specifically, the core does not have enough storage to store a complete checkpoint of all the architected state for all four threads. The DD2.2 version of POWER9 includes hardware modifications designed to allow hypervisor software to implement workarounds for these problems. This patch implements those workarounds in KVM code so that KVM guests see a full, working transactional memory implementation. The problems center around the use of TM suspended state, where the CPU has a checkpointed state but execution is not transactional. The workaround is to implement a "fake suspend" state, which looks to the guest like suspended state but the CPU does not store a checkpoint. In this state, any instruction that would cause a transition to transactional state (rfid, rfebb, mtmsrd, tresume) or would use the checkpointed state (treclaim) causes a "soft patch" interrupt (vector 0x1500) to the hypervisor so that it can be emulated. The trechkpt instruction also causes a soft patch interrupt. On POWER9 DD2.2, we avoid returning to the guest in any state which would require a checkpoint to be present. The trechkpt in the guest entry path which would normally create that checkpoint is replaced by either a transition to fake suspend state, if the guest is in suspend state, or a rollback to the pre-transactional state if the guest is in transactional state. Fake suspend state is indicated by a flag in the PACA plus a new bit in the PSSCR. The new PSSCR bit is write-only and reads back as 0. On exit from the guest, if the guest is in fake suspend state, we still do the treclaim instruction as we would in real suspend state, in order to get into non-transactional state, but we do not save the resulting register state since there was no checkpoint. Emulation of the instructions that cause a softpatch interrupt is handled in two paths. If the guest is in real suspend mode, we call kvmhv_p9_tm_emulation_early() to handle the cases where the guest is transitioning to transactional state. This is called before we do the treclaim in the guest exit path; because we haven't done treclaim, we can get back to the guest with the transaction still active. If the instruction is a case that kvmhv_p9_tm_emulation_early() doesn't handle, or if the guest is in fake suspend state, then we proceed to do the complete guest exit path and subsequently call kvmhv_p9_tm_emulation() in host context with the MMU on. This handles all the cases including the cases that generate program interrupts (illegal instruction or TM Bad Thing) and facility unavailable interrupts. The emulation is reasonably straightforward and is mostly concerned with checking for exception conditions and updating the state of registers such as MSR and CR0. The treclaim emulation takes care to ensure that the TEXASR register gets updated as if it were the guest treclaim instruction that had done failure recording, not the treclaim done in hypervisor state in the guest exit path. With this, the KVM_CAP_PPC_HTM capability returns true (1) even if transactional memory is not available to host userspace. Signed-off-by: Paul Mackerras Signed-off-by: Michael Ellerman

KVM: PPC: Book3S HV: Run HPT guests on POWER9 radix hosts

2017-11-01T04:36:41Z

This patch removes the restriction that a radix host can only run radix guests, allowing us to run HPT (hashed page table) guests as well. This is useful because it provides a way to run old guest kernels that know about POWER8 but not POWER9. Unfortunately, POWER9 currently has a restriction that all threads in a given code must either all be in HPT mode, or all in radix mode. This means that when entering a HPT guest, we have to obtain control of all 4 threads in the core and get them to switch their LPIDR and LPCR registers, even if they are not going to run a guest. On guest exit we also have to get all threads to switch LPIDR and LPCR back to host values. To make this feasible, we require that KVM not be in the "independent threads" mode, and that the CPU cores be in single-threaded mode from the host kernel's perspective (only thread 0 online; threads 1, 2 and 3 offline). That allows us to use the same code as on POWER8 for obtaining control of the secondary threads. To manage the LPCR/LPIDR changes required, we extend the kvm_split_info struct to contain the information needed by the secondary threads. All threads perform a barrier synchronization (where all threads wait for every other thread to reach the synchronization point) on guest entry, both before and after loading LPCR and LPIDR. On guest exit, they all once again perform a barrier synchronization both before and after loading host values into LPCR and LPIDR. Finally, it is also currently necessary to flush the entire TLB every time we enter a HPT guest on a radix host. We do this on thread 0 with a loop of tlbiel instructions. Signed-off-by: Paul Mackerras

Revert "KVM: PPC: Book3S HV: POWER9 does not require secondary thread management"

2017-10-19T04:28:04Z

This reverts commit 94a04bc25a2c6296bd0c5e82c10e8231c2b11f77. In order to run HPT guests on a radix POWER9 host, we will have to run the host in single-threaded mode, because POWER9 processors do not currently support running some threads of a core in HPT mode while others are in radix mode ("mixed mode"). That means that we will need the same mechanisms that are used on POWER8 to make the secondary threads available to KVM, which were disabled on POWER9 by commit 94a04bc25a2c. Signed-off-by: Paul Mackerras Signed-off-by: Michael Ellerman