Re: [PATCH v1 4/9] Add RDT functionality

[Jonathan Cameron via <qemu-devel@nongnu.org>]

On Fri, 19 Jul 2024 16:29:24 +0000
Hendrik Wuethrich <whendrik@google.com> wrote:

> From: ‪Hendrik Wüthrich <whendrik@google.com>
> 
> Add RDT code to Associate CLOSID with RMID / set RMID for monitoring,
> write COS, and read monitoring data. This patch does not add code for
> the guest to interact through these things with MSRs, only the actual
> ability for the RDT device to do them.
> 
> Signed-off-by: Hendrik Wüthrich <whendrik@google.com>
> ---
>  hw/i386/rdt.c         | 124 ++++++++++++++++++++++++++++++++++++++++++
>  include/hw/i386/rdt.h |  13 +++++
>  2 files changed, 137 insertions(+)
> 
> diff --git a/hw/i386/rdt.c b/hw/i386/rdt.c
> index 259dafc963..77b7b4f2d4 100644
> --- a/hw/i386/rdt.c
> +++ b/hw/i386/rdt.c
> @@ -7,6 +7,11 @@
>  #include "target/i386/cpu.h"
>  #include "hw/isa/isa.h"
>  
> +/* RDT Monitoring Event Codes */
> +#define RDT_EVENT_L3_OCCUPANCY 1
> +#define RDT_EVENT_L3_REMOTE_BW 2
> +#define RDT_EVENT_L3_LOCAL_BW 3
> +
>  /* Max counts for allocation masks or CBMs. In other words, the size of respective MSRs*/
>  #define MAX_L3_MASK_COUNT      128
>  #define MAX_L2_MASK_COUNT      48
> @@ -15,6 +20,9 @@
>  #define TYPE_RDT "rdt"
>  #define RDT_NUM_RMID_PROP "rmids"
>  
> +#define QM_CTR_Error        (1ULL << 63)
> +#define QM_CTR_Unavailable  (1ULL << 62)

Mix of capitals and camel case is a bit unusual. I'd go
capitals throughout unless there is precedence.

Also, prefix with RDT_QM probably so we know it's a local
define where it is used.

> +
>  OBJECT_DECLARE_TYPE(RDTState, RDTStateClass, RDT);
>  
>  struct RDTMonitor {
> @@ -49,6 +57,122 @@ struct RDTState {
>  
>  struct RDTStateClass { };
>  
> +bool rdt_associate_rmid_cos(uint64_t msr_ia32_pqr_assoc) {
> +    X86CPU *cpu = X86_CPU(current_cpu);
> +    RDTStateInstance *rdt = cpu->rdt;
> +    RDTAllocation *alloc;
> +
> +    uint32_t cos_id = (msr_ia32_pqr_assoc & 0xffff0000) >> 16;
> +    uint32_t rmid = msr_ia32_pqr_assoc & 0xffff;
> +
> +    if (cos_id > MAX_L3_MASK_COUNT || cos_id > MAX_L2_MASK_COUNT ||
> +    cos_id > MAX_MBA_THRTL_COUNT || rmid > rdt_max_rmid(rdt)) {

Fix indent to be
       if (cos_id...
           cos_id > ...


> +        return false;
> +    }
> +
> +    rdt->active_rmid = rmid;
> +
> +    alloc = &g_array_index(rdt->rdtstate->allocations, RDTAllocation, rmid);
> +
> +    alloc->active_cos = cos_id;
> +
> +    return true;
> +}
> +
> +uint32_t rdt_read_l3_mask(uint32_t pos)
> +{
> +    X86CPU *cpu = X86_CPU(current_cpu);
> +    RDTStateInstance *rdt = cpu->rdt;
> +
> +    uint32_t val = rdt->rdtstate->msr_L3_ia32_mask_n[pos];
> +    return val;

return rdt->

> +}
> +
> +uint32_t rdt_read_l2_mask(uint32_t pos)
> +{
> +    X86CPU *cpu = X86_CPU(current_cpu);
> +    RDTStateInstance *rdt = cpu->rdt;
> +
> +    uint32_t val = rdt->rdtstate->msr_L2_ia32_mask_n[pos];
> +    return val;

return rdt->

> +}
> +
> +uint32_t rdt_read_mba_thrtl(uint32_t pos)
> +{
> +    X86CPU *cpu = X86_CPU(current_cpu);
> +    RDTStateInstance *rdt = cpu->rdt;
> +
> +    uint32_t val = rdt->rdtstate->ia32_L2_qos_ext_bw_thrtl_n[pos];
> +    return val;

return rdt->rdstate...

> +}
> +
> +void rdt_write_msr_l3_mask(uint32_t pos, uint32_t val) {
> +    X86CPU *cpu = X86_CPU(current_cpu);
> +    RDTStateInstance *rdt = cpu->rdt;
> +
> +    rdt->rdtstate->msr_L3_ia32_mask_n[pos] = val;
> +}
> +
> +void rdt_write_msr_l2_mask(uint32_t pos, uint32_t val) {
> +    X86CPU *cpu = X86_CPU(current_cpu);
> +    RDTStateInstance *rdt = cpu->rdt;
> +
> +    rdt->rdtstate->msr_L2_ia32_mask_n[pos] = val;
> +}
> +
> +void rdt_write_mba_thrtl(uint32_t pos, uint32_t val) {
> +    X86CPU *cpu = X86_CPU(current_cpu);
> +    RDTStateInstance *rdt = cpu->rdt;
> +
> +    rdt->rdtstate->ia32_L2_qos_ext_bw_thrtl_n[pos] = val;
> +}
> +
> +uint32_t rdt_max_rmid(RDTStateInstance *rdt)
> +{
> +    RDTState *rdtdev = rdt->rdtstate;
> +    return rdtdev->rmids - 1;
> +}
> +
> +uint64_t rdt_read_event_count(RDTStateInstance *rdtInstance, uint32_t rmid, uint32_t event_id)

Long line - consider wrapping it.

> +{
> +    CPUState *cs;
> +    RDTMonitor *mon;
> +    RDTState *rdt = rdtInstance->rdtstate;
> +
> +    uint32_t count_l3 = 0;
> +    uint32_t count_local= 0;
> +    uint32_t count_remote = 0;
> +
> +    if (!rdt) {
> +        return 0;
> +    }
> +
> +    CPU_FOREACH(cs) {
> +        rdtInstance = &g_array_index(rdt->rdtInstances, RDTStateInstance, cs->cpu_index);
> +        if (rmid >= rdtInstance->monitors->len) {
> +            return QM_CTR_Error;
> +        }
> +        mon = &g_array_index(rdtInstance->monitors, RDTMonitor, rmid);
> +        count_l3 += mon->count_l3;
> +        count_local += mon->count_local;
> +        count_remote += mon->count_remote;
> +    }
> +
> +    switch (event_id) {
> +        case RDT_EVENT_L3_OCCUPANCY:
> +            return count_l3 == 0 ? QM_CTR_Unavailable : count_l3;
> +            break;
> +        case RDT_EVENT_L3_REMOTE_BW:
> +            return count_remote == 0 ? QM_CTR_Unavailable : count_remote;
> +            break;
> +        case RDT_EVENT_L3_LOCAL_BW:
> +            return count_local == 0 ? QM_CTR_Unavailable : count_local;
> +            break;

break after return not needed. I'm a bit surprised that didn't give you a warning.


> +        default:
> +            return QM_CTR_Error;
> +    }
> +}
> +
>  OBJECT_DEFINE_TYPE(RDTState, rdt, RDT, ISA_DEVICE);
>  
>  static Property rdt_properties[] = {
> diff --git a/include/hw/i386/rdt.h b/include/hw/i386/rdt.h
> index 45e34d3103..8092c5f290 100644
> --- a/include/hw/i386/rdt.h
> +++ b/include/hw/i386/rdt.h
> @@ -10,3 +10,16 @@ typedef struct RDTMonitor RDTMonitor;
>  typedef struct RDTAllocation RDTAllocation;
>  
>  #endif
> +bool rdt_associate_rmid_cos(uint64_t msr_ia32_pqr_assoc);
> +
> +void rdt_write_msr_l3_mask(uint32_t pos, uint32_t val);
> +void rdt_write_msr_l2_mask(uint32_t pos, uint32_t val);
> +void rdt_write_mba_thrtl(uint32_t pos, uint32_t val);
> +
> +uint32_t rdt_read_l3_mask(uint32_t pos);
> +uint32_t rdt_read_l2_mask(uint32_t pos);
> +uint32_t rdt_read_mba_thrtl(uint32_t pos);
> +
> +uint64_t rdt_read_event_count(RDTStateInstance *rdt, uint32_t rmid, uint32_t event_id);
> +uint32_t rdt_max_rmid(RDTStateInstance *rdt);
> +
Trailing blank line doesn't add anything so I'd drop it.

Jonathan