Re: [PATCH 4/7] target/arm/hvf: Add KVMID_TO_HVF, HVF_TO_KVMID

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 18/8/25 06:13, Richard Henderson wrote:
> Conversion between KVM system registers ids and the HVF system
> register ids is trivial.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   target/arm/hvf/hvf.c | 20 ++++++++++++++++++++
>   1 file changed, 20 insertions(+)
> 
> diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
> index f0e4b75e6a..2577dc1c0c 100644
> --- a/target/arm/hvf/hvf.c
> +++ b/target/arm/hvf/hvf.c
> @@ -403,6 +403,26 @@ struct hvf_sreg_match {
>       uint32_t cp_idx;
>   };
>   
> +/*
> + * QEMU uses KVM system register ids in the migration format.
> + * Conveniently, HVF uses the same encoding of the op* and cr* parameters
> + * within the low 16 bits of the ids.  Thus conversion between the
> + * formats is trivial.
> + */
> +
> +#define KVMID_TO_HVF(KVM)  ((KVM) & 0xffff)
> +#define HVF_TO_KVMID(HVF)  \
> +    (CP_REG_ARM64 | CP_REG_SIZE_U64 | CP_REG_ARM64_SYSREG | (HVF))
> +
> +/* Verify this at compile-time. */
> +
> +#define DEF_SYSREG(HVF_ID, ...) \
> +  QEMU_BUILD_BUG_ON(HVF_ID != KVMID_TO_HVF(KVMID_AA64_SYS_REG64(__VA_ARGS__)));

Rebasing Mohamed's work I'm getting:

In file included from ../../target/arm/hvf/hvf.c:413:
../../target/arm/hvf/sysreg.c.inc:156:1: error: static assertion failed 
due to requirement '!(HV_SYS_REG_MDCR_EL2 != (((((1 << 28) | (19 << 16) 
| ((3) << 14) | ((4) << 11) | ((1) << 7) | ((1) << 3) | ((1) << 0)) | 
13510798882111488ULL)) & 65535))': not expecting: HV_SYS_REG_MDCR_EL2 != 
KVMID_TO_HVF(KVMID_AA64_SYS_REG64(1, 1, 3, 4, 1))
   156 | DEF_SYSREG(HV_SYS_REG_MDCR_EL2, 1, 1, 3, 4, 1)
       | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Having in <Hypervisor.h> -> <Hypervisor/hv_vcpu_types.h>:
     // Exception Level 2 (EL2) registers.
     // These registers are only available if EL2 was enabled in the VM 
configuration.
     HV_SYS_REG_CNTHCTL_EL2 = 0xe708,
     HV_SYS_REG_CNTHP_CTL_EL2 = 0xe711,
     HV_SYS_REG_CNTHP_CVAL_EL2 = 0xe712,
     HV_SYS_REG_CNTHP_TVAL_EL2 = 0xe710,
     HV_SYS_REG_CNTVOFF_EL2 = 0xe703,
     HV_SYS_REG_CPTR_EL2 = 0xe08a,
     HV_SYS_REG_ELR_EL2 = 0xe201,
     HV_SYS_REG_ESR_EL2 = 0xe290,
     HV_SYS_REG_FAR_EL2 = 0xe300,
     HV_SYS_REG_HCR_EL2 = 0xe088,
     HV_SYS_REG_HPFAR_EL2 = 0xe304,
     HV_SYS_REG_MAIR_EL2 = 0xe510,
     HV_SYS_REG_MDCR_EL2 = 0xe019,   <----
     HV_SYS_REG_SCTLR_EL2 = 0xe080,
     HV_SYS_REG_SPSR_EL2 = 0xe200,
     HV_SYS_REG_SP_EL2 = 0xf208,
     HV_SYS_REG_TCR_EL2 = 0xe102,
     HV_SYS_REG_TPIDR_EL2 = 0xe682,
     HV_SYS_REG_TTBR0_EL2 = 0xe100,
     HV_SYS_REG_TTBR1_EL2 = 0xe101,
     HV_SYS_REG_VBAR_EL2 = 0xe600,
     HV_SYS_REG_VMPIDR_EL2 = 0xe005,
     HV_SYS_REG_VPIDR_EL2 = 0xe000,
     HV_SYS_REG_VTCR_EL2 = 0xe10a,
     HV_SYS_REG_VTTBR_EL2 = 0xe108,

> +
> +#include "sysreg.c.inc"
> +
> +#undef DEF_SYSREG
> +
>   #define DEF_SYSREG(HVF_ID, crn, crm, op0, op1, op2) \
>       { HVF_ID, HVF_SYSREG(crn, crm, op0, op1, op2) },
>