Re: [PATCH 1/2] x86/vmx: Calculate model-specific LBRs once at start of day

[Jan Beulich <jbeulich@xxxxxxxx>]

On 09.01.2023 13:08, Andrew Cooper wrote:
> There is no point repeating this calculation at runtime, especially as it is
> in the fallback path of the WRSMR/RDMSR handlers.
> 
> Move the infrastructure higher in vmx.c to avoid forward declarations,
> renaming last_branch_msr_get() to get_model_specific_lbr() to highlight that
> these are model-specific only.
> 
> No practical change.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
with one nit:

> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -396,6 +396,142 @@ void vmx_pi_hooks_deassign(struct domain *d)
>      domain_unpause(d);
>  }
>  
> +static const struct lbr_info {
> +    u32 base, count;
> +} p4_lbr[] = {
> +    { MSR_P4_LER_FROM_LIP,          1 },
> +    { MSR_P4_LER_TO_LIP,            1 },
> +    { MSR_P4_LASTBRANCH_TOS,        1 },
> +    { MSR_P4_LASTBRANCH_0_FROM_LIP, NUM_MSR_P4_LASTBRANCH_FROM_TO },
> +    { MSR_P4_LASTBRANCH_0_TO_LIP,   NUM_MSR_P4_LASTBRANCH_FROM_TO },
> +    { 0, 0 }
> +}, c2_lbr[] = {
> +    { MSR_IA32_LASTINTFROMIP,       1 },
> +    { MSR_IA32_LASTINTTOIP,         1 },
> +    { MSR_C2_LASTBRANCH_TOS,        1 },
> +    { MSR_C2_LASTBRANCH_0_FROM_IP,  NUM_MSR_C2_LASTBRANCH_FROM_TO },
> +    { MSR_C2_LASTBRANCH_0_TO_IP,    NUM_MSR_C2_LASTBRANCH_FROM_TO },
> +    { 0, 0 }
> +}, nh_lbr[] = {
> +    { MSR_IA32_LASTINTFROMIP,       1 },
> +    { MSR_IA32_LASTINTTOIP,         1 },
> +    { MSR_NHL_LBR_SELECT,           1 },
> +    { MSR_NHL_LASTBRANCH_TOS,       1 },
> +    { MSR_P4_LASTBRANCH_0_FROM_LIP, NUM_MSR_P4_LASTBRANCH_FROM_TO },
> +    { MSR_P4_LASTBRANCH_0_TO_LIP,   NUM_MSR_P4_LASTBRANCH_FROM_TO },
> +    { 0, 0 }
> +}, sk_lbr[] = {
> +    { MSR_IA32_LASTINTFROMIP,       1 },
> +    { MSR_IA32_LASTINTTOIP,         1 },
> +    { MSR_NHL_LBR_SELECT,           1 },
> +    { MSR_NHL_LASTBRANCH_TOS,       1 },
> +    { MSR_SKL_LASTBRANCH_0_FROM_IP, NUM_MSR_SKL_LASTBRANCH },
> +    { MSR_SKL_LASTBRANCH_0_TO_IP,   NUM_MSR_SKL_LASTBRANCH },
> +    { MSR_SKL_LASTBRANCH_0_INFO,    NUM_MSR_SKL_LASTBRANCH },
> +    { 0, 0 }
> +}, at_lbr[] = {
> +    { MSR_IA32_LASTINTFROMIP,       1 },
> +    { MSR_IA32_LASTINTTOIP,         1 },
> +    { MSR_C2_LASTBRANCH_TOS,        1 },
> +    { MSR_C2_LASTBRANCH_0_FROM_IP,  NUM_MSR_ATOM_LASTBRANCH_FROM_TO },
> +    { MSR_C2_LASTBRANCH_0_TO_IP,    NUM_MSR_ATOM_LASTBRANCH_FROM_TO },
> +    { 0, 0 }
> +}, sm_lbr[] = {
> +    { MSR_IA32_LASTINTFROMIP,       1 },
> +    { MSR_IA32_LASTINTTOIP,         1 },
> +    { MSR_SM_LBR_SELECT,            1 },
> +    { MSR_SM_LASTBRANCH_TOS,        1 },
> +    { MSR_C2_LASTBRANCH_0_FROM_IP,  NUM_MSR_ATOM_LASTBRANCH_FROM_TO },
> +    { MSR_C2_LASTBRANCH_0_TO_IP,    NUM_MSR_ATOM_LASTBRANCH_FROM_TO },
> +    { 0, 0 }
> +}, gm_lbr[] = {
> +    { MSR_IA32_LASTINTFROMIP,       1 },
> +    { MSR_IA32_LASTINTTOIP,         1 },
> +    { MSR_SM_LBR_SELECT,            1 },
> +    { MSR_SM_LASTBRANCH_TOS,        1 },
> +    { MSR_GM_LASTBRANCH_0_FROM_IP,  NUM_MSR_GM_LASTBRANCH_FROM_TO },
> +    { MSR_GM_LASTBRANCH_0_TO_IP,    NUM_MSR_GM_LASTBRANCH_FROM_TO },
> +    { 0, 0 }
> +};
> +static const struct lbr_info * __ro_after_init model_specific_lbr;
> +
> +static const struct __init lbr_info *get_model_specific_lbr(void)

Please move __init:

static const struct lbr_info *__init get_model_specific_lbr(void)

Jan