[PATCH v10 0/5] Support writable CPU ID registers from userspace
From: Jing Zhang <hidden>
Date: 2023-05-22 22:19:09
Also in:
kvm, kvmarm
This patchset refactors/adds code to support writable per guest CPU ID feature registers. Part of the code/ideas are from https://lore.kernel.org/all/20220419065544.3616948-1-reijiw@google.com (local) . No functional change is intended in this patchset. With the new CPU ID feature registers infrastructure, only writtings of ID_AA64PFR0_EL1.[CSV2|CSV3], ID_AA64DFR0_EL1.PMUVer and ID_DFR0_ELF.PerfMon are allowed as KVM does before. Writable (Configurable) per guest CPU ID feature registers are useful for creating/migrating guest on ARM CPUs with different kinds of features. This patchset uses kvm->arch.config_lock from Oliver's lock inversion fixes at https://lore.kernel.org/linux-arm-kernel/20230327164747.2466958-1-oliver.upton@linux.dev/ (local) --- * v9 - v10 - Rebased to v6.4-rc3 - Addressed some review comments from v8/v9. * v8 -> v9 - Rebased to v6.4-rc2. - Don't create new file id_regs.c and don't move out id regs from sys_reg_descs array to reduce the changes. * v7 -> v8 - Move idregs table sanity check to kvm_sys_reg_table_init. - Only allow userspace writing before VM running. - No lock is hold for guest access to idregs. - Addressed some other comments from Reiji and Oliver. * v6 -> v7 - Rebased to v6.3-rc7. - Add helpers for idregs read/write. - Guard all idregs reads/writes. - Add code to fix features' safe value type which is different for KVM than for the host. * v5 -> v6 - Rebased to v6.3-rc5. - Reuse struct sys_reg_desc's reset() callback and field val for KVM. sanitisation function and writable mask instead of creating a new data structure for idregs. - Use get_arm64_ftr_reg() instead of exposing idregs ftr_bits array. * v4 -> v5 - Rebased to 2fad20ae05cb (kvmarm/next) Merge branch kvm-arm64/selftest/misc-6,4 into kvmarm-master/next - Use kvm->arch.config_lock to guard update to multiple VM scope idregs to avoid lock inversion - Add back IDREG() macro for idregs access - Refactor struct id_reg_desc by using existing infrastructure. - Addressed many other comments from Marc. * v3 -> v4 - Remove IDREG() macro for ID reg access, use simple array access instead - Rename kvm_arm_read_id_reg_with_encoding() to kvm_arm_read_id_reg() - Save perfmon value in ID_DFR0_EL1 instead of pmuver - Update perfmon in ID_DFR0_EL1 and pmuver in ID_AA64DFR0_EL1 atomically - Remove kvm_vcpu_has_pmu() in macro kvm_pmu_is_3p5() - Improve ID register sanity checking in kvm_arm_check_idreg_table() * v2 -> v3 - Rebased to 96a4627dbbd4 (kvmarm/next) Merge tag ' https://github.com/oupton/linux tags/kvmarm-6.3' from into kvmarm-master/next - Add id registere emulation entry point function emulate_id_reg - Fix consistency for ID_AA64DFR0_EL1.PMUVer and ID_DFR0_EL1.PerfMon - Improve the checking for id register table by ensuring that every entry has the correct id register encoding. - Addressed other comments from Reiji and Marc. * v1 -> v2 - Rebase to 7121a2e1d107 (kvmarm/next) Merge branch kvm-arm64/nv-prefix into kvmarm/next - Address writing issue for PMUVer [1] https://lore.kernel.org/all/20230201025048.205820-1-jingzhangos@google.com (local) [2] https://lore.kernel.org/all/20230212215830.2975485-1-jingzhangos@google.com (local) [3] https://lore.kernel.org/all/20230228062246.1222387-1-jingzhangos@google.com (local) [4] https://lore.kernel.org/all/20230317050637.766317-1-jingzhangos@google.com (local) [5] https://lore.kernel.org/all/20230402183735.3011540-1-jingzhangos@google.com (local) [6] https://lore.kernel.org/all/20230404035344.4043856-1-jingzhangos@google.com (local) [7] https://lore.kernel.org/all/20230424234704.2571444-1-jingzhangos@google.com (local) [8] https://lore.kernel.org/all/20230503171618.2020461-1-jingzhangos@google.com (local) [9] https://lore.kernel.org/all/20230517061015.1915934-1-jingzhangos@google.com (local) --- Jing Zhang (5): KVM: arm64: Save ID registers' sanitized value per guest KVM: arm64: Use per guest ID register for ID_AA64PFR0_EL1.[CSV2|CSV3] KVM: arm64: Use per guest ID register for ID_AA64DFR0_EL1.PMUVer KVM: arm64: Reuse fields of sys_reg_desc for idreg KVM: arm64: Refactor writings for PMUVer/CSV2/CSV3 arch/arm64/include/asm/cpufeature.h | 1 + arch/arm64/include/asm/kvm_host.h | 34 +- arch/arm64/kernel/cpufeature.c | 2 +- arch/arm64/kvm/arm.c | 24 +- arch/arm64/kvm/sys_regs.c | 469 +++++++++++++++++++++++----- arch/arm64/kvm/sys_regs.h | 22 +- include/kvm/arm_pmu.h | 5 +- 7 files changed, 437 insertions(+), 120 deletions(-) base-commit: 44c026a73be8038f03dbdeef028b642880cf1511 -- 2.40.1.698.g37aff9b760-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel