Re: [PATCH v3 3/3] arm64/kvm: Fine grain _EL2 system registers list that affect nested virtualization

[Marc Zyngier <maz@kernel.org>]

On 2023-10-16 11:11, Miguel Luis wrote:
> Hi Eric,
> 
>> On 16 Oct 2023, at 09:54, Eric Auger <eric.auger@redhat.com> wrote:
>> 
>> Hi Miguel,
>> 
>> On 10/13/23 20:41, Miguel Luis wrote:
>>> Hi Eric,
>>> 
>>>> On 12 Oct 2023, at 15:22, Eric Auger <eric.auger@redhat.com> wrote:
>>>> 
>>>> Hi Miguel,
>>>> 
>>>> On 10/11/23 20:01, Miguel Luis wrote:
>>>>> Implement a fine grained approach in the _EL2 sysreg ranges.
>>>>> 
>>>>> Fixes: d0fc0a2519a6 ("KVM: arm64: nv: Add trap forwarding for 
>>>>> HCR_EL2")
>>>>> Signed-off-by: Miguel Luis <miguel.luis@oracle.com>
>>>>> ---
>>>>> arch/arm64/kvm/emulate-nested.c | 88 
>>>>> ++++++++++++++++++++++++++++++---
>>>>> 1 file changed, 82 insertions(+), 6 deletions(-)
>>>>> 
>>>>> diff --git a/arch/arm64/kvm/emulate-nested.c 
>>>>> b/arch/arm64/kvm/emulate-nested.c
>>>>> index 9ced1bf0c2b7..3af49e130ee6 100644
>>>>> --- a/arch/arm64/kvm/emulate-nested.c
>>>>> +++ b/arch/arm64/kvm/emulate-nested.c
>>>>> @@ -648,15 +648,91 @@ static const struct encoding_to_trap_config 
>>>>> encoding_to_cgt[] __initconst = {
>>>>> SR_TRAP(SYS_APGAKEYLO_EL1, CGT_HCR_APK),
>>>>> SR_TRAP(SYS_APGAKEYHI_EL1, CGT_HCR_APK),
>>>>> /* All _EL2 registers */
>>>>> - SR_RANGE_TRAP(sys_reg(3, 4, 0, 0, 0),
>>>>> -       sys_reg(3, 4, 3, 15, 7), CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_VPIDR_EL2, CGT_HCR_NV),
>>>> I think you miss DBGVCR32_EL2
>>> That would be op0 == 10, which I indeed didn't considered given the 
>>> ranges
>>> previously defined. From its pseudocode I see it would make sense 
>>> only if EL1
>>> would support AArch32 but that seems not to be in the plans.
>>> 
>>>>> + SR_TRAP(SYS_VMPIDR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_SCTLR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_ACTLR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_SCTLR2_EL2, CGT_HCR_NV),
>>>>> + SR_RANGE_TRAP(SYS_HCR_EL2,
>>>>> +       SYS_HCRX_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_SMPRIMAP_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_SMCR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_SDER32_EL2, CGT_HCR_NV),
>>>>> + SR_RANGE_TRAP(SYS_TTBR0_EL2,
>>>>> +       SYS_TCR2_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_VTTBR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_VTCR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_VNCR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_VSTTBR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_VSTCR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_DACR32_EL2, CGT_HCR_NV),
>>>>> + SR_RANGE_TRAP(SYS_HDFGRTR_EL2,
>>>>> +       SYS_HAFGRTR_EL2, CGT_HCR_NV),
>>>>> /* Skip the SP_EL1 encoding... */
>>>>> SR_TRAP(SYS_SPSR_EL2, CGT_HCR_NV),
>>>>> SR_TRAP(SYS_ELR_EL2, CGT_HCR_NV),
>>>>> - SR_RANGE_TRAP(sys_reg(3, 4, 4, 1, 1),
>>>>> -       sys_reg(3, 4, 10, 15, 7), CGT_HCR_NV),
>>>>> - SR_RANGE_TRAP(sys_reg(3, 4, 12, 0, 0),
>>>>> -       sys_reg(3, 4, 14, 15, 7), CGT_HCR_NV),
>>>>> + /* SPSR_irq, SPSR_abt, SPSR_und, SPSR_fiq */
>>>>> + SR_RANGE_TRAP(sys_reg(3, 4, 4, 3, 0),
>>>>> +       sys_reg(3, 4, 4, 3, 3), CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_IFSR32_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_AFSR0_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_AFSR1_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_ESR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_VSESR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_FPEXC32_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_TFSR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_FAR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_HPFAR_EL2, CGT_HCR_NV),
>>>> you miss BRBCR_EL2
>>> Yes, definitely. Same as above, didn't considered op0 == 10, (Table 
>>> D18-1).
>>> This one seems to me the only one missing too.
>> 
>> yep
> 
> Thanks for confirming it!
> 
>>> 
>>>>> + SR_TRAP(SYS_PMSCR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_MAIR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_AMAIR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_MPAMHCR_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_MPAMVPMV_EL2, CGT_HCR_NV),
>>>>> + SR_TRAP(SYS_MPAM2_EL2, CGT_HCR_NV),
>>>>> + SR_RANGE_TRAP(SYS_MPAMVPM0_EL2,
>>>>> +       SYS_MPAMVPM7_EL2, CGT_HCR_NV),
>>>> About the MPAM where did you find the pseudo code?
>>> The pseucode isn't available on the document. I'm following the 
>>> statement when
>>> HCR_EL2.NV is 1, where:
>>> 
>>> "The System or Special-purpose registers for which accesses are 
>>> trapped and
>>> reported using EC syndrome value 0x18 are as follows:
>>> — Registers accessed using MRS or MSR with a name ending in _EL2, 
>>> except, [...]"
>> 
>> ok thank you for the clarification. With
>> 
>> BRBCR_EL2 handling, feel free to add my
>> 
>> Reviewed-by: Eric Auger <eric.auger@redhat.com>
>> 
> 
> Thank you Eric!
> 
>> (I guess you will handle
>> DBGVCR32_EL2 in a separate patch)
>> 
> 
> I think that Marc is addressing it here:
> https://lore.kernel.org/kvmarm/20231013223311.3950585-1-maz@kernel.org/
> but I can be wrong.
> 
> Marc, could you please confirm ?

Indeed, that's the fix. If you respin this series *now*, I can take
this patch and your series as a set of fixes for 6.6.

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...