[PATCH v8 00/69] KVM: arm64: ARMv8.3/8.4 Nested Virtualization support
Marc Zyngier
maz at kernel.org
Tue Jan 31 01:23:55 PST 2023
This is the second drop of NV support on arm64 for this year. This
month even. Something is happening!
For the previous episodes, see [1].
What's changed:
- TLB invalidation has been fixed! A couple of terrible bugs were
preventing the TLBI emulation code from selecting the correct MMU
context, leading the shadow page-tables never being invalidated.
- As a consequence, EDK2 now works correctly at L2 with QEMU as the
VMM, as we now teardown the S2 PTs when L1 unmaps the memslot on
write to the emulated flash.
- As a consequence of the above consequence, the Debian installer
passes with flying colors at L2. Yay!
- A few other fixes, such as better handling of AT instructions.
- All rebased on 6.2-rc4 + kvmarm-fixes-6.2-* + kvmarm/next. Full
branch at [2].
Performance:
- This is surprisingly good. Specially after years of watching paint
dry in a model. Of course, if your workload is exit/trap heavy, it
will suck. But not quite as much as on the model, which is the
benchmark.
- For CPU intensive workloads (kernel compilation), I have seen as
little a 6% overhead between L0 and L2. YMMV.
Testing:
- No model involved this time around. I have solely run the series on
an Apple M2 with 16k pages, because that's what I have, and I
consider it the reference (HW you cannot get your hands on doesn't
really count).
- Because the M2 is "pretty lax" with the architecture, a bunch of
things cannot be tested (E2H=0 being the most obvious one).
- For the same reason, I may be relying on non-architectural
behaviours. I've done my best not to, but you never know. Until I
get a machine that *is* fully compliant with the architecture, it is
a risk I'll have to take.
- The series has a number of hacks for the M2 to actually work (vgic
emulation, mostly).
- I haven't tested FEAT_NV (only FEAT_NV2), and seriously considering
dropping the support for it. I doubt there is any HW solely
implementing FEAT_NV and not FEAT_NV2.
- There is a kvmtool branch that allows you to use the --nested option
at [3]. I have no idea what became of the equivalent QEMU patches.
Merging:
- I would suggest that the first 12 patches are in a mergeable
state. Only patch #2 hasn't been reviewed yet (because it is new),
but it doesn't affect anything non-NV and makes NV work. I really
want this in before CCA! :D
- I have a yet another fix for the Apple AIC driver, but I'll post
that separately.
Many thanks to Alexandru, Chase, Ganapatrao and Russell for spending a
lot of time reviewing this, spotting issues and providing helpful
suggestions.
[1] https://lore.kernel.org/r/20230112191927.1814989-1-maz@kernel.org
[2] git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git kvm-arm64/nv-6.3-WIP
[3] https://git.kernel.org/pub/scm/linux/kernel/git/maz/kvmtool.git/log/?h=arm64/nv-5.16
Andre Przywara (1):
KVM: arm64: nv: vgic: Allow userland to set VGIC maintenance IRQ
Christoffer Dall (13):
KVM: arm64: nv: Introduce nested virtualization VCPU feature
KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set
KVM: arm64: nv: Allow userspace to set PSR_MODE_EL2x
KVM: arm64: nv: Add nested virt VCPU primitives for vEL2 VCPU state
KVM: arm64: nv: Reset VMPIDR_EL2 and VPIDR_EL2 to sane values
KVM: arm64: nv: Handle trapped ERET from virtual EL2
KVM: arm64: nv: Trap EL1 VM register accesses in virtual EL2
KVM: arm64: nv: Only toggle cache for virtual EL2 when SCTLR_EL2
changes
KVM: arm64: nv: Implement nested Stage-2 page table walk logic
KVM: arm64: nv: Unmap/flush shadow stage 2 page tables
KVM: arm64: nv: vgic: Emulate the HW bit in software
KVM: arm64: nv: Add nested GICv3 tracepoints
KVM: arm64: nv: Sync nested timer state with FEAT_NV2
Jintack Lim (16):
arm64: Add ARM64_HAS_NESTED_VIRT cpufeature
KVM: arm64: nv: Handle HCR_EL2.NV system register traps
KVM: arm64: nv: Support virtual EL2 exceptions
KVM: arm64: nv: Inject HVC exceptions to the virtual EL2
KVM: arm64: nv: Add accessors for SPSR_EL1, ELR_EL1 and VBAR_EL1 from
virtual EL2
KVM: arm64: nv: Trap CPACR_EL1 access in virtual EL2
KVM: arm64: nv: Handle PSCI call via smc from the guest
KVM: arm64: nv: Respect virtual HCR_EL2.TWX setting
KVM: arm64: nv: Respect virtual CPTR_EL2.{TFP,FPEN} settings
KVM: arm64: nv: Respect the virtual HCR_EL2.NV bit setting
KVM: arm64: nv: Respect virtual HCR_EL2.TVM and TRVM settings
KVM: arm64: nv: Respect the virtual HCR_EL2.NV1 bit setting
KVM: arm64: nv: Emulate EL12 register accesses from the virtual EL2
KVM: arm64: nv: Configure HCR_EL2 for nested virtualization
KVM: arm64: nv: Trap and emulate TLBI instructions from virtual EL2
KVM: arm64: nv: Nested GICv3 Support
Marc Zyngier (39):
KVM: arm64: Use the S2 MMU context to iterate over S2 table
KVM: arm64: nv: Add EL2 system registers to vcpu context
KVM: arm64: nv: Add non-VHE-EL2->EL1 translation helpers
KVM: arm64: nv: Handle virtual EL2 registers in
vcpu_read/write_sys_reg()
KVM: arm64: nv: Handle SPSR_EL2 specially
KVM: arm64: nv: Handle HCR_EL2.E2H specially
KVM: arm64: nv: Save/Restore vEL2 sysregs
KVM: arm64: nv: Emulate PSTATE.M for a guest hypervisor
KVM: arm64: nv: Allow a sysreg to be hidden from userspace only
KVM: arm64: nv: Forward debug traps to the nested guest
KVM: arm64: nv: Filter out unsupported features from ID regs
KVM: arm64: nv: Hide RAS from nested guests
KVM: arm64: nv: Support multiple nested Stage-2 mmu structures
KVM: arm64: nv: Handle shadow stage 2 page faults
KVM: arm64: nv: Restrict S2 RD/WR permissions to match the guest's
KVM: arm64: nv: Set a handler for the system instruction traps
KVM: arm64: nv: Trap and emulate AT instructions from virtual EL2
KVM: arm64: nv: Fold guest's HCR_EL2 configuration into the host's
KVM: arm64: nv: arch_timer: Support hyp timer emulation
KVM: arm64: nv: Add handling of EL2-specific timer registers
KVM: arm64: nv: Load timer before the GIC
KVM: arm64: nv: Don't load the GICv4 context on entering a nested
guest
KVM: arm64: nv: Implement maintenance interrupt forwarding
KVM: arm64: nv: Deal with broken VGIC on maintenance interrupt
delivery
KVM: arm64: nv: Allow userspace to request KVM_ARM_VCPU_NESTED_VIRT
KVM: arm64: nv: Add handling of FEAT_TTL TLB invalidation
KVM: arm64: nv: Invalidate TLBs based on shadow S2 TTL-like
information
KVM: arm64: nv: Tag shadow S2 entries with nested level
KVM: arm64: nv: Add include containing the VNCR_EL2 offsets
KVM: arm64: nv: Map VNCR-capable registers to a separate page
KVM: arm64: nv: Move nested vgic state into the sysreg file
KVM: arm64: Add FEAT_NV2 cpu feature
KVM: arm64: nv: Publish emulated timer interrupt state in the
in-memory state
KVM: arm64: nv: Allocate VNCR page when required
KVM: arm64: nv: Enable ARMv8.4-NV support
KVM: arm64: nv: Fast-track 'InHost' exception returns
KVM: arm64: nv: Fast-track EL1 TLBIs for VHE guests
KVM: arm64: nv: Use FEAT_ECV to trap access to EL0 timers
KVM: arm64: nv: Accelerate EL0 timer read accesses when FEAT_ECV is on
.../admin-guide/kernel-parameters.txt | 7 +-
.../virt/kvm/devices/arm-vgic-v3.rst | 12 +-
arch/arm64/include/asm/esr.h | 5 +
arch/arm64/include/asm/kvm_arm.h | 27 +-
arch/arm64/include/asm/kvm_asm.h | 4 +
arch/arm64/include/asm/kvm_emulate.h | 159 +-
arch/arm64/include/asm/kvm_host.h | 195 ++-
arch/arm64/include/asm/kvm_hyp.h | 2 +
arch/arm64/include/asm/kvm_mmu.h | 23 +-
arch/arm64/include/asm/kvm_nested.h | 150 ++
arch/arm64/include/asm/sysreg.h | 102 +-
arch/arm64/include/asm/vncr_mapping.h | 74 +
arch/arm64/include/uapi/asm/kvm.h | 2 +
arch/arm64/kernel/cpufeature.c | 36 +
arch/arm64/kvm/Makefile | 4 +-
arch/arm64/kvm/arch_timer.c | 301 +++-
arch/arm64/kvm/arm.c | 38 +-
arch/arm64/kvm/at.c | 221 +++
arch/arm64/kvm/emulate-nested.c | 217 +++
arch/arm64/kvm/guest.c | 6 +
arch/arm64/kvm/handle_exit.c | 74 +-
arch/arm64/kvm/hyp/exception.c | 48 +-
arch/arm64/kvm/hyp/include/hyp/switch.h | 12 +-
arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 24 +-
arch/arm64/kvm/hyp/nvhe/switch.c | 2 +-
arch/arm64/kvm/hyp/nvhe/sysreg-sr.c | 2 +-
arch/arm64/kvm/hyp/vgic-v3-sr.c | 2 +-
arch/arm64/kvm/hyp/vhe/switch.c | 230 ++-
arch/arm64/kvm/hyp/vhe/sysreg-sr.c | 125 +-
arch/arm64/kvm/hyp/vhe/tlb.c | 83 +
arch/arm64/kvm/inject_fault.c | 61 +-
arch/arm64/kvm/mmu.c | 259 +++-
arch/arm64/kvm/nested.c | 896 +++++++++++
arch/arm64/kvm/reset.c | 17 +
arch/arm64/kvm/sys_regs.c | 1377 ++++++++++++++++-
arch/arm64/kvm/sys_regs.h | 14 +-
arch/arm64/kvm/trace_arm.h | 65 +-
arch/arm64/kvm/vgic/vgic-init.c | 33 +
arch/arm64/kvm/vgic/vgic-kvm-device.c | 29 +-
arch/arm64/kvm/vgic/vgic-nested-trace.h | 137 ++
arch/arm64/kvm/vgic/vgic-v3-nested.c | 244 +++
arch/arm64/kvm/vgic/vgic-v3.c | 39 +-
arch/arm64/kvm/vgic/vgic.c | 44 +
arch/arm64/kvm/vgic/vgic.h | 10 +
arch/arm64/tools/cpucaps | 2 +
include/clocksource/arm_arch_timer.h | 4 +
include/kvm/arm_arch_timer.h | 9 +-
include/kvm/arm_vgic.h | 16 +
include/uapi/linux/kvm.h | 1 +
tools/arch/arm/include/uapi/asm/kvm.h | 1 +
50 files changed, 5221 insertions(+), 224 deletions(-)
create mode 100644 arch/arm64/include/asm/kvm_nested.h
create mode 100644 arch/arm64/include/asm/vncr_mapping.h
create mode 100644 arch/arm64/kvm/at.c
create mode 100644 arch/arm64/kvm/emulate-nested.c
create mode 100644 arch/arm64/kvm/nested.c
create mode 100644 arch/arm64/kvm/vgic/vgic-nested-trace.h
create mode 100644 arch/arm64/kvm/vgic/vgic-v3-nested.c
--
2.34.1
More information about the linux-arm-kernel
mailing list