2025-05-23T17:29:49+02:00, Clément Léger cleger@rivosinc.com:
On 23/05/2025 15:05, Radim Krčmář wrote:
2025-05-23T12:19:30+02:00, Clément Léger cleger@rivosinc.com:
+++ b/arch/riscv/kvm/vcpu_sbi_fwft.c +static const enum sbi_fwft_feature_t kvm_fwft_defined_features[] = {
- SBI_FWFT_MISALIGNED_EXC_DELEG,
- SBI_FWFT_LANDING_PAD,
- SBI_FWFT_SHADOW_STACK,
- SBI_FWFT_DOUBLE_TRAP,
- SBI_FWFT_PTE_AD_HW_UPDATING,
- SBI_FWFT_POINTER_MASKING_PMLEN,
+};
How will userspace control which subset of these features is allowed in the guest?
(We can reuse the KVM SBI extension interface if we don't want to add a FWFT specific ONE_REG.)
Hi Radim,
I didn't looked at that part. But most likely using the kvm one reg interface seems ok like what is done for STA ? We could have per feature override with one reg per feature.
Sounds fine.
Is this something blocking though ? We'd like to merge FWFT once SBI 3.0 is ratified so that would be nice not delaying it too much. I'll take a look at it to see if it isn't too long to implement.
Not blocking, but I would at least default FWFT to disabled, because current userspace cannot handle [14/14]. (Well... save/restore was probably broken even before, but let's try to not make it worse. :])
Thanks.