Re: [PATCH v4 00/15] arm64: Support for running as a guest in Arm CCA

Shanker Donthineni
2024-08-15T22:16:30Z

Hi Steven,

On 7/12/24 03:54, Matias Ezequiel Vara Larsen wrote:
> On Mon, Jul 01, 2024 at 10:54:50AM +0100, Steven Price wrote:
>> This series adds support for running Linux in a protected VM under the
>> Arm Confidential Compute Architecture (CCA). This has been updated
>> following the feedback from the v3 posting[1]. Thanks for the feedback!
>> Individual patches have a change log. But things to highlight:
>>
>> * a new patch ("firmware/psci: Add psci_early_test_conduit()") to
>> prevent SMC calls being made on systems which don't support them -
>> i.e. systems without EL2/EL3 - thanks Jean-Philippe!
>>
>> * two patches dropped (overriding set_fixmap_io). Instead
>> FIXMAP_PAGE_IO is modified to include PROT_NS_SHARED. When support
>> for assigning hardware devices to a realm guest is added this will
>> need to be brought back in some form. But for now it's just adding
>> complixity and confusion for no gain.
>>
>> * a new patch ("arm64: mm: Avoid TLBI when marking pages as valid")
>> which avoids doing an extra TLBI when doing the break-before-make.
>> Note that this changes the behaviour in other cases when making
>> memory valid. This should be safe (and saves a TLBI for those cases),
>> but it's a separate patch in case of regressions.
>>
>> * GIC ITT allocation now uses a custom genpool-based allocator. I
>> expect this will be replaced with a generic way of allocating
>> decrypted memory (see [4]), but for now this gets things working
>> without wasting too much memory.
>>
>> The ABI to the RMM from a realm (the RSI) is based on the final RMM v1.0
>> (EAC 5) specification[2]. Future RMM specifications will be backwards
>> compatible so a guest using the v1.0 specification (i.e. this series)
>> will be able to run on future versions of the RMM without modification.
>>
>> This series is based on v6.10-rc1. It is also available as a git
>> repository:
>>
>> https://gitlab.arm.com/linux-arm/linux-cca cca-guest/v4

Which cca-host branch should I use for testing cca-guest/v4?

I'm getting compilation errors with cca-host/v3 and cca-guest/v4, is there
any known WAR or fix to resolve this issue?

arch/arm64/kvm/rme.c: In function ‘kvm_realm_reset_id_aa64dfr0_el1’:
././include/linux/compiler_types.h:487:45: error: call to ‘__compiletime_assert_650’ declared with attribute error: FIELD_PREP: value too large for the field
487 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
././include/linux/compiler_types.h:468:25: note: in definition of macro ‘__compiletime_assert’
468 | prefix ## suffix(); \
| ^~~~~~
././include/linux/compiler_types.h:487:9: note: in expansion of macro ‘_compiletime_assert’
487 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
./include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
./include/linux/bitfield.h:68:17: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
68 | BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \
| ^~~~~~~~~~~~~~~~
./include/linux/bitfield.h:115:17: note: in expansion of macro ‘__BF_FIELD_CHECK’
115 | __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \
| ^~~~~~~~~~~~~~~~
arch/arm64/kvm/rme.c:315:16: note: in expansion of macro ‘FIELD_PREP’
315 | val |= FIELD_PREP(ID_AA64DFR0_EL1_BRPs_MASK, bps - 1) |
| ^~~~~~~~~~
make[5]: *** [scripts/Makefile.build:244: arch/arm64/kvm/rme.o] Error 1
make[4]: *** [scripts/Makefile.build:485: arch/arm64/kvm] Error 2
make[3]: *** [scripts/Makefile.build:485: arch/arm64] Error 2
make[3]: *** Waiting for unfinished jobs....

I'm using gcc-13.3.0 compiler and cross-compiling on X86 machine.

-Shanker