Hey!
I've decided to start messing around with nested and have SVE support
working for a nested guest. For the sake of landing a semi-complete
feature upstream, I've also picked up the FPSIMD patches from the NV
series Marc is carrying.
The most annoying part about this series (IMO) is that ZCR_EL2 traps
behave differently from what needs to be virtualized for the guest when
HCR_EL2.NV = 1, as it takes a sysreg trap (EC = 0x18) instead of an SVE
trap (EC = 0x19). So, we need to synthesize the ESR value when
reflecting back into the guest hypervisor.
Otherwise, some care is required to slap the guest hypervisor's ZCR_EL2
into the right place depending on whether or not the vCPU is in a hyp
context, since it affects the hyp's usage of SVE in addition to the VM.
There's more work to be done for honoring the L1's CPTR traps, as this
series only focuses on getting SVE and FPSIMD traps right. We'll get
there one day.
I tested this using a mix of the fpsimd-test and sve-test selftests
running at L0, L1, and L2 concurrently on Neoverse V2.
Jintack Lim (1):
KVM: arm64: nv: Forward FP/ASIMD traps to guest hypervisor
Oliver Upton (10):
KVM: arm64: nv: Forward SVE traps to guest hypervisor
KVM: arm64: nv: Load guest FP state for ZCR_EL2 trap
KVM: arm64: nv: Load guest hyp's ZCR into EL1 state
KVM: arm64: nv: Handle ZCR_EL2 traps
KVM: arm64: nv: Save guest's ZCR_EL2 when in hyp context
KVM: arm64: nv: Use guest hypervisor's max VL when running nested
guest
KVM: arm64: nv: Ensure correct VL is loaded before saving SVE state
KVM: arm64: Spin off helper for programming CPTR traps
KVM: arm64: nv: Honor guest hypervisor's FP/SVE traps in CPTR_EL2
KVM: arm64: Allow the use of SVE+NV
arch/arm64/include/asm/kvm_emulate.h | 47 +++++++++++++++++++
arch/arm64/include/asm/kvm_host.h | 7 +++
arch/arm64/include/asm/kvm_nested.h | 1 -
arch/arm64/kvm/arm.c | 5 --
arch/arm64/kvm/fpsimd.c | 22 +++++++--
arch/arm64/kvm/handle_exit.c | 19 ++++++--
arch/arm64/kvm/hyp/include/hyp/switch.h | 43 ++++++++++++++++-
arch/arm64/kvm/hyp/vhe/switch.c | 62 +++++++++++++++----------
arch/arm64/kvm/nested.c | 3 +-
arch/arm64/kvm/sys_regs.c | 40 ++++++++++++++++
10 files changed, 206 insertions(+), 43 deletions(-)
base-commit: 1613e604df0cd359cf2a7fbd9be7a0bcfacfabd0
--
2.45.1.288.g0e0cd299f1-goog
