Thread (67 messages) 67 messages, 3 authors, 2022-02-10

Re: [RFC PATCH v4 00/26] KVM: arm64: Make CPU ID registers writable by userspace

From: Reiji Watanabe <hidden>
Date: 2022-01-25 06:32:47
Also in: kvm, kvmarm

Hi Fuad,

On Mon, Jan 24, 2022 at 8:19 AM Fuad Tabba [off-list ref] wrote:
Hi Reiji,

On Thu, Jan 6, 2022 at 4:27 AM Reiji Watanabe [off-list ref] wrote:
quoted
The patch series is for both VHE and non-VHE, except for protected VMs,
which have a different way of configuring ID registers based on its
different requirements [1].
I am reviewing this patch series and I really like your approach. I
think that once it's through we might be able to generalize it for
protected VMs as well (I did some of the work for the ID registers for
those).
Thank you for the review and comments for the series.
I will be looking at your comments.
quoted
The series is based on v5.16-rc8 with the patch [3] applied.
I tried to apply this series on v5.16-rc8 after applying
20220104194918.373612-2-rananta@google.com, and it didn't apply
cleanly. If you could point me to a working branch that I could
checkout I would like to test it and experiment with it a bit more.
I'm sorry for the inconvenience.  I'm not sure why though...
I tried that again (applied the series on v5.16-rc8 after applying
20220104194918.373612-2-rananta@google.com), and it worked fine.

Anyway, you can find the branch at:
 https://github.com/reijiw-kvm/kvmarm-idreg/tree/id-regs-v4-5.16-rc8

Thanks,
Reiji



quoted
v4:
  - Make ID registers storage per VM instead of per vCPU. [Marc]
  - Implement arm64_check_features() in arch/arm64/kernel/cpufeature.c
    by using existing codes in the file. [Marc]
  - Use a configuration function to enable traps for disabled
    features. [Marc]
  - Document ID registers become immutable after the first KVM_RUN [Eric]
  - Update ID_AA64PFR0.GIC at the point where a GICv3 is created. [Marc]
  - Get TGranX's bit position by substracting 12 from TGranX_2's bit
    position. [Eric]
  - Don't validate AArch32 ID registers when the system doesn't support
    32bit EL0. [Eric]
  - Add/fixes comments for patches. [Eric]
  - Made bug fixes/improvements of the selftest. [Eric]
  - Added .kunitconfig for arm64 KUnit tests

v3: https://lore.kernel.org/all/20211117064359.2362060-1-reijiw@google.com/ (local)
  - Remove ID register consistency checking across vCPUs. [Oliver]
  - Change KVM_CAP_ARM_ID_REG_WRITABLE to
    KVM_CAP_ARM_ID_REG_CONFIGURABLE. [Oliver]
  - Add KUnit testing for ID register validation and trap initialization.
  - Change read_id_reg() to take care of ID_AA64PFR0_EL1.GIC.
  - Add a helper of read_id_reg() (__read_id_reg()) and use the helper
    instead of directly using __vcpu_sys_reg().
  - Change not to run kvm_id_regs_consistency_check() and
    kvm_vcpu_init_traps() for protected VMs.
  - Update selftest to remove test cases for ID register consistency.
    checking across vCPUs and to add test cases for ID_AA64PFR0_EL1.GIC.

v2: https://lore.kernel.org/all/20211103062520.1445832-1-reijiw@google.com/ (local)
  - Remove unnecessary line breaks. [Andrew]
  - Use @params for comments. [Andrew]
  - Move arm64_check_features to arch/arm64/kvm/sys_regs.c and
    change that KVM specific feature check function.  [Andrew]
  - Remove unnecessary raz handling from __set_id_reg. [Andrew]
  - Remove sys_val field from the initial id_reg_info and add it
    in the later patch. [Andrew]
  - Call id_reg->init() from id_reg_info_init(). [Andrew]
  - Fix cpuid_feature_cap_perfmon_field() to convert 0xf to 0x0
    (and use it in the following patches).
  - Change kvm_vcpu_first_run_init to set has_run_once to false
    when kvm_id_regs_consistency_check() fails.
  - Add a patch to introduce id_reg_info for ID_AA64MMFR0_EL1,
    which requires special validity checking for TGran*_2 fields.
  - Add patches to introduce id_reg_info for ID_DFR1_EL1 and
    ID_MMFR0_EL1, which are required due to arm64_check_features
    implementation change.
  - Add a new argument, which is a pointer to id_reg_info, for
    id_reg_info's validate().

v1: https://lore.kernel.org/all/20211012043535.500493-1-reijiw@google.com/ (local)

[1] https://lore.kernel.org/kvmarm/20211010145636.1950948-1-tabba@google.com/ (local)
[2] https://lore.kernel.org/kvm/20201102033422.657391-1-liangpeng10@huawei.com/ (local)
[3] https://lore.kernel.org/all/20220104194918.373612-2-rananta@google.com/ (local)

Reiji Watanabe (26):
  KVM: arm64: Introduce a validation function for an ID register
  KVM: arm64: Save ID registers' sanitized value per guest
  KVM: arm64: Introduce struct id_reg_info
  KVM: arm64: Make ID_AA64PFR0_EL1 writable
  KVM: arm64: Make ID_AA64PFR1_EL1 writable
  KVM: arm64: Make ID_AA64ISAR0_EL1 writable
  KVM: arm64: Make ID_AA64ISAR1_EL1 writable
  KVM: arm64: Make ID_AA64MMFR0_EL1 writable
  KVM: arm64: Hide IMPLEMENTATION DEFINED PMU support for the guest
  KVM: arm64: Make ID_AA64DFR0_EL1 writable
  KVM: arm64: Make ID_DFR0_EL1 writable
  KVM: arm64: Make MVFR1_EL1 writable
  KVM: arm64: Make ID registers without id_reg_info writable
  KVM: arm64: Add consistency checking for frac fields of ID registers
  KVM: arm64: Introduce KVM_CAP_ARM_ID_REG_CONFIGURABLE capability
  KVM: arm64: Add kunit test for ID register validation
  KVM: arm64: Use vcpu->arch cptr_el2 to track value of cptr_el2 for VHE
  KVM: arm64: Use vcpu->arch.mdcr_el2 to track value of mdcr_el2
  KVM: arm64: Introduce framework to trap disabled features
  KVM: arm64: Trap disabled features of ID_AA64PFR0_EL1
  KVM: arm64: Trap disabled features of ID_AA64PFR1_EL1
  KVM: arm64: Trap disabled features of ID_AA64DFR0_EL1
  KVM: arm64: Trap disabled features of ID_AA64MMFR1_EL1
  KVM: arm64: Trap disabled features of ID_AA64ISAR1_EL1
  KVM: arm64: Add kunit test for trap initialization
  KVM: arm64: selftests: Introduce id_reg_test

 Documentation/virt/kvm/api.rst                |   12 +
 arch/arm64/include/asm/cpufeature.h           |    3 +-
 arch/arm64/include/asm/kvm_arm.h              |   32 +
 arch/arm64/include/asm/kvm_host.h             |   19 +
 arch/arm64/include/asm/sysreg.h               |    3 +
 arch/arm64/kernel/cpufeature.c                |  228 +++
 arch/arm64/kvm/.kunitconfig                   |    4 +
 arch/arm64/kvm/Kconfig                        |   11 +
 arch/arm64/kvm/arm.c                          |   24 +-
 arch/arm64/kvm/debug.c                        |   13 +-
 arch/arm64/kvm/hyp/vhe/switch.c               |   14 +-
 arch/arm64/kvm/sys_regs.c                     | 1329 +++++++++++++++--
 arch/arm64/kvm/sys_regs_test.c                | 1247 ++++++++++++++++
 arch/arm64/kvm/vgic/vgic-init.c               |    5 +
 include/uapi/linux/kvm.h                      |    1 +
 tools/arch/arm64/include/asm/sysreg.h         |    1 +
 tools/testing/selftests/kvm/.gitignore        |    1 +
 tools/testing/selftests/kvm/Makefile          |    1 +
 .../selftests/kvm/aarch64/id_reg_test.c       | 1239 +++++++++++++++
 19 files changed, 4041 insertions(+), 146 deletions(-)
 create mode 100644 arch/arm64/kvm/.kunitconfig
 create mode 100644 arch/arm64/kvm/sys_regs_test.c
 create mode 100644 tools/testing/selftests/kvm/aarch64/id_reg_test.c


base-commit: d399b107ee49bf5ea0391bd7614d512809e927b0
--
2.34.1.448.ga2b2bfdf31-goog

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