diff mbox series

[v4,09/42] hw/cxl/device: Timestamp implementation (8.2.9.3)

Message ID 20220124171705.10432-10-Jonathan.Cameron@huawei.com
State Superseded
Headers show
Series CXl 2.0 emulation Support | expand

Commit Message

Jonathan Cameron Jan. 24, 2022, 5:16 p.m. UTC
From: Ben Widawsky <ben.widawsky@intel.com>

Per spec, timestamp appears to be a free-running counter from a value
set by the host via the Set Timestamp command (0301h). There are
references to the epoch, which seem like a red herring. Therefore, the
implementation implements the timestamp as freerunning counter from the
last value that was issued by the Set Timestamp command.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 hw/cxl/cxl-mailbox-utils.c  | 53 +++++++++++++++++++++++++++++++++++++
 include/hw/cxl/cxl_device.h |  6 +++++
 2 files changed, 59 insertions(+)

Comments

Alex Bennée Jan. 27, 2022, 11:50 a.m. UTC | #1
Jonathan Cameron <Jonathan.Cameron@huawei.com> writes:

> From: Ben Widawsky <ben.widawsky@intel.com>
>
> Per spec, timestamp appears to be a free-running counter from a value
> set by the host via the Set Timestamp command (0301h). There are
> references to the epoch, which seem like a red herring. Therefore, the
> implementation implements the timestamp as freerunning counter from the
> last value that was issued by the Set Timestamp command.
>
> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> ---
>  hw/cxl/cxl-mailbox-utils.c  | 53 +++++++++++++++++++++++++++++++++++++
>  include/hw/cxl/cxl_device.h |  6 +++++
>  2 files changed, 59 insertions(+)
>
> diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
> index 1a87846356..cea4b2a59c 100644
> --- a/hw/cxl/cxl-mailbox-utils.c
> +++ b/hw/cxl/cxl-mailbox-utils.c
> @@ -43,6 +43,9 @@ enum {
>          #define CLEAR_RECORDS   0x1
>          #define GET_INTERRUPT_POLICY   0x2
>          #define SET_INTERRUPT_POLICY   0x3
> +    TIMESTAMP   = 0x03,
> +        #define GET           0x0
> +        #define SET           0x1
>  };
>  
>  /* 8.2.8.4.5.1 Command Return Codes */
> @@ -117,8 +120,11 @@ define_mailbox_handler_zeroed(EVENTS_GET_RECORDS, 0x20);
>  define_mailbox_handler_nop(EVENTS_CLEAR_RECORDS);
>  define_mailbox_handler_zeroed(EVENTS_GET_INTERRUPT_POLICY, 4);
>  define_mailbox_handler_nop(EVENTS_SET_INTERRUPT_POLICY);
> +declare_mailbox_handler(TIMESTAMP_GET);
> +declare_mailbox_handler(TIMESTAMP_SET);
>  
>  #define IMMEDIATE_CONFIG_CHANGE (1 << 1)
> +#define IMMEDIATE_POLICY_CHANGE (1 << 3)
>  #define IMMEDIATE_LOG_CHANGE (1 << 4)
>  
>  #define CXL_CMD(s, c, in, cel_effect) \
> @@ -129,10 +135,57 @@ static struct cxl_cmd cxl_cmd_set[256][256] = {
>      CXL_CMD(EVENTS, CLEAR_RECORDS, ~0, IMMEDIATE_LOG_CHANGE),
>      CXL_CMD(EVENTS, GET_INTERRUPT_POLICY, 0, 0),
>      CXL_CMD(EVENTS, SET_INTERRUPT_POLICY, 4, IMMEDIATE_CONFIG_CHANGE),
> +    CXL_CMD(TIMESTAMP, GET, 0, 0),
> +    CXL_CMD(TIMESTAMP, SET, 8, IMMEDIATE_POLICY_CHANGE),
>  };
>  
>  #undef CXL_CMD
>  
> +/*
> + * 8.2.9.3.1
> + */
> +define_mailbox_handler(TIMESTAMP_GET)
> +{
> +    struct timespec ts;
> +    uint64_t delta;
> +
> +    if (!cxl_dstate->timestamp.set) {
> +        *(uint64_t *)cmd->payload = 0;
> +        goto done;
> +    }
> +
> +    /* First find the delta from the last time the host set the time. */
> +    clock_gettime(CLOCK_REALTIME, &ts);

Could you consider using qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)?
Otherwise by introducing a dependency on real time you'll loose the
ability to get deterministic execution via icount. 

> +    delta = (ts.tv_sec * NANOSECONDS_PER_SECOND + ts.tv_nsec) -
> +            cxl_dstate->timestamp.last_set;
> +
> +    /* Then adjust the actual time */
> +    stq_le_p(cmd->payload, cxl_dstate->timestamp.host_set + delta);
> +
> +done:
> +    *len = 8;
> +    return CXL_MBOX_SUCCESS;
> +}
> +
> +/*
> + * 8.2.9.3.2
> + */
> +define_mailbox_handler(TIMESTAMP_SET)
> +{
> +    struct timespec ts;
> +
> +    clock_gettime(CLOCK_REALTIME, &ts);
> +
> +    cxl_dstate->timestamp.set = true;
> +    cxl_dstate->timestamp.last_set =
> +        ts.tv_sec * NANOSECONDS_PER_SECOND + ts.tv_nsec;
> +
> +    cxl_dstate->timestamp.host_set = le64_to_cpu(*(uint64_t *)cmd->payload);
> +
> +    *len = 0;
> +    return CXL_MBOX_SUCCESS;
> +}
> +
>  QemuUUID cel_uuid;
>  
>  void cxl_process_mailbox(CXLDeviceState *cxl_dstate)
> diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
> index f88f844cb6..3dde7fb1fb 100644
> --- a/include/hw/cxl/cxl_device.h
> +++ b/include/hw/cxl/cxl_device.h
> @@ -114,6 +114,12 @@ typedef struct cxl_device_state {
>          size_t cel_size;
>      };
>  
> +    struct {
> +        bool set;
> +        uint64_t last_set;
> +        uint64_t host_set;
> +    } timestamp;
> +
>      /* memory region for persistent memory, HDM */
>      uint64_t pmem_size;
>  } CXLDeviceState;
Jonathan Cameron Jan. 28, 2022, 5:52 p.m. UTC | #2
On Thu, 27 Jan 2022 11:50:08 +0000
Alex Bennée <alex.bennee@linaro.org> wrote:

> Jonathan Cameron <Jonathan.Cameron@huawei.com> writes:
> 
> > From: Ben Widawsky <ben.widawsky@intel.com>
> >
> > Per spec, timestamp appears to be a free-running counter from a value
> > set by the host via the Set Timestamp command (0301h). There are
> > references to the epoch, which seem like a red herring. Therefore, the
> > implementation implements the timestamp as freerunning counter from the
> > last value that was issued by the Set Timestamp command.
> >
> > Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > ---
> >  hw/cxl/cxl-mailbox-utils.c  | 53 +++++++++++++++++++++++++++++++++++++
> >  include/hw/cxl/cxl_device.h |  6 +++++
> >  2 files changed, 59 insertions(+)
> >
> > diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
> > index 1a87846356..cea4b2a59c 100644
> > --- a/hw/cxl/cxl-mailbox-utils.c
> > +++ b/hw/cxl/cxl-mailbox-utils.c
> > @@ -43,6 +43,9 @@ enum {
> >          #define CLEAR_RECORDS   0x1
> >          #define GET_INTERRUPT_POLICY   0x2
> >          #define SET_INTERRUPT_POLICY   0x3
> > +    TIMESTAMP   = 0x03,
> > +        #define GET           0x0
> > +        #define SET           0x1
> >  };
> >  
> >  /* 8.2.8.4.5.1 Command Return Codes */
> > @@ -117,8 +120,11 @@ define_mailbox_handler_zeroed(EVENTS_GET_RECORDS, 0x20);
> >  define_mailbox_handler_nop(EVENTS_CLEAR_RECORDS);
> >  define_mailbox_handler_zeroed(EVENTS_GET_INTERRUPT_POLICY, 4);
> >  define_mailbox_handler_nop(EVENTS_SET_INTERRUPT_POLICY);
> > +declare_mailbox_handler(TIMESTAMP_GET);
> > +declare_mailbox_handler(TIMESTAMP_SET);
> >  
> >  #define IMMEDIATE_CONFIG_CHANGE (1 << 1)
> > +#define IMMEDIATE_POLICY_CHANGE (1 << 3)
> >  #define IMMEDIATE_LOG_CHANGE (1 << 4)
> >  
> >  #define CXL_CMD(s, c, in, cel_effect) \
> > @@ -129,10 +135,57 @@ static struct cxl_cmd cxl_cmd_set[256][256] = {
> >      CXL_CMD(EVENTS, CLEAR_RECORDS, ~0, IMMEDIATE_LOG_CHANGE),
> >      CXL_CMD(EVENTS, GET_INTERRUPT_POLICY, 0, 0),
> >      CXL_CMD(EVENTS, SET_INTERRUPT_POLICY, 4, IMMEDIATE_CONFIG_CHANGE),
> > +    CXL_CMD(TIMESTAMP, GET, 0, 0),
> > +    CXL_CMD(TIMESTAMP, SET, 8, IMMEDIATE_POLICY_CHANGE),
> >  };
> >  
> >  #undef CXL_CMD
> >  
> > +/*
> > + * 8.2.9.3.1
> > + */
> > +define_mailbox_handler(TIMESTAMP_GET)
> > +{
> > +    struct timespec ts;
> > +    uint64_t delta;
> > +
> > +    if (!cxl_dstate->timestamp.set) {
> > +        *(uint64_t *)cmd->payload = 0;
> > +        goto done;
> > +    }
> > +
> > +    /* First find the delta from the last time the host set the time. */
> > +    clock_gettime(CLOCK_REALTIME, &ts);  
> 
> Could you consider using qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)?
> Otherwise by introducing a dependency on real time you'll loose the
> ability to get deterministic execution via icount.

I don't have a strong opinion either way, so Ill go with 
qemu_clock_get_ns() and see if any comments on it in v5.

I've also updated the commit message as the catch all errata
which was F4 included a clarification that the timestamp
was as implemented here.

Thanks,

Jonathan
diff mbox series

Patch

diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
index 1a87846356..cea4b2a59c 100644
--- a/hw/cxl/cxl-mailbox-utils.c
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -43,6 +43,9 @@  enum {
         #define CLEAR_RECORDS   0x1
         #define GET_INTERRUPT_POLICY   0x2
         #define SET_INTERRUPT_POLICY   0x3
+    TIMESTAMP   = 0x03,
+        #define GET           0x0
+        #define SET           0x1
 };
 
 /* 8.2.8.4.5.1 Command Return Codes */
@@ -117,8 +120,11 @@  define_mailbox_handler_zeroed(EVENTS_GET_RECORDS, 0x20);
 define_mailbox_handler_nop(EVENTS_CLEAR_RECORDS);
 define_mailbox_handler_zeroed(EVENTS_GET_INTERRUPT_POLICY, 4);
 define_mailbox_handler_nop(EVENTS_SET_INTERRUPT_POLICY);
+declare_mailbox_handler(TIMESTAMP_GET);
+declare_mailbox_handler(TIMESTAMP_SET);
 
 #define IMMEDIATE_CONFIG_CHANGE (1 << 1)
+#define IMMEDIATE_POLICY_CHANGE (1 << 3)
 #define IMMEDIATE_LOG_CHANGE (1 << 4)
 
 #define CXL_CMD(s, c, in, cel_effect) \
@@ -129,10 +135,57 @@  static struct cxl_cmd cxl_cmd_set[256][256] = {
     CXL_CMD(EVENTS, CLEAR_RECORDS, ~0, IMMEDIATE_LOG_CHANGE),
     CXL_CMD(EVENTS, GET_INTERRUPT_POLICY, 0, 0),
     CXL_CMD(EVENTS, SET_INTERRUPT_POLICY, 4, IMMEDIATE_CONFIG_CHANGE),
+    CXL_CMD(TIMESTAMP, GET, 0, 0),
+    CXL_CMD(TIMESTAMP, SET, 8, IMMEDIATE_POLICY_CHANGE),
 };
 
 #undef CXL_CMD
 
+/*
+ * 8.2.9.3.1
+ */
+define_mailbox_handler(TIMESTAMP_GET)
+{
+    struct timespec ts;
+    uint64_t delta;
+
+    if (!cxl_dstate->timestamp.set) {
+        *(uint64_t *)cmd->payload = 0;
+        goto done;
+    }
+
+    /* First find the delta from the last time the host set the time. */
+    clock_gettime(CLOCK_REALTIME, &ts);
+    delta = (ts.tv_sec * NANOSECONDS_PER_SECOND + ts.tv_nsec) -
+            cxl_dstate->timestamp.last_set;
+
+    /* Then adjust the actual time */
+    stq_le_p(cmd->payload, cxl_dstate->timestamp.host_set + delta);
+
+done:
+    *len = 8;
+    return CXL_MBOX_SUCCESS;
+}
+
+/*
+ * 8.2.9.3.2
+ */
+define_mailbox_handler(TIMESTAMP_SET)
+{
+    struct timespec ts;
+
+    clock_gettime(CLOCK_REALTIME, &ts);
+
+    cxl_dstate->timestamp.set = true;
+    cxl_dstate->timestamp.last_set =
+        ts.tv_sec * NANOSECONDS_PER_SECOND + ts.tv_nsec;
+
+    cxl_dstate->timestamp.host_set = le64_to_cpu(*(uint64_t *)cmd->payload);
+
+    *len = 0;
+    return CXL_MBOX_SUCCESS;
+}
+
 QemuUUID cel_uuid;
 
 void cxl_process_mailbox(CXLDeviceState *cxl_dstate)
diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
index f88f844cb6..3dde7fb1fb 100644
--- a/include/hw/cxl/cxl_device.h
+++ b/include/hw/cxl/cxl_device.h
@@ -114,6 +114,12 @@  typedef struct cxl_device_state {
         size_t cel_size;
     };
 
+    struct {
+        bool set;
+        uint64_t last_set;
+        uint64_t host_set;
+    } timestamp;
+
     /* memory region for persistent memory, HDM */
     uint64_t pmem_size;
 } CXLDeviceState;