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Re: [PATCH for-5.0 v11 12/20] qapi: Introduce DEFINE_PROP_INTERVAL
From: |
Auger Eric |
Subject: |
Re: [PATCH for-5.0 v11 12/20] qapi: Introduce DEFINE_PROP_INTERVAL |
Date: |
Thu, 12 Dec 2019 16:13:06 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
Hi Markus,
On 12/12/19 1:17 PM, Markus Armbruster wrote:
> Eric Auger <address@hidden> writes:
>
>> Introduce a new property defining a labelled interval:
>> <low address>,<high address>,label.
>>
>> This will be used to encode reserved IOVA regions. The label
>> is left undefined to ease reuse accross use cases.
>
> What does the last sentence mean?
The dilemma was shall I specialize this property such as ReservedRegion
or shall I leave it generic enough to serve somebody else use case. I
first chose the latter but now I think I should rather call it something
like ReservedRegion as in any case it has addresses and an integer label.
>
>> For instance, in virtio-iommu use case, reserved IOVA regions
>> will be passed by the machine code to the virtio-iommu-pci
>> device (an array of those). The label will match the
>> virtio_iommu_probe_resv_mem subtype value:
>> - VIRTIO_IOMMU_RESV_MEM_T_RESERVED (0)
>> - VIRTIO_IOMMU_RESV_MEM_T_MSI (1)
>>
>> This is used to inform the virtio-iommu-pci device it should
>> bypass the MSI region: 0xfee00000, 0xfeefffff, 1.
>
> So the "label" part of "<low address>,<high address>,label" is a number?
yes it is.
>
> Is a number appropriate for your use case, or would an enum be better?
I think a number is OK. There might be other types of reserved regions
in the future. Also if we want to allow somebody else to reuse that
property in another context, I would rather leave it open?
>
>>
>> Signed-off-by: Eric Auger <address@hidden> ---
>> hw/core/qdev-properties.c | 90 ++++++++++++++++++++++++++++++++++++
>> include/exec/memory.h | 6 +++ include/hw/qdev-properties.h | 3 ++
>> include/qemu/typedefs.h | 1 + 4 files changed, 100 insertions(+)
>
> Subject has 'qapi:', but it's actually about qdev. Please adjust the subject.
OK
>
>> diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
>> index ac28890e5a..8d70f34e37 100644
>> --- a/hw/core/qdev-properties.c
>> +++ b/hw/core/qdev-properties.c
>> @@ -13,6 +13,7 @@
>> #include "qapi/visitor.h"
>> #include "chardev/char.h"
>> #include "qemu/uuid.h"
>> +#include "qemu/cutils.h"
>>
>> void qdev_prop_set_after_realize(DeviceState *dev, const char *name,
>> Error **errp)
>> @@ -585,6 +586,95 @@ const PropertyInfo qdev_prop_macaddr = {
>> .set = set_mac,
>> };
>>
>> +/* --- Labelled Interval --- */
>> +
>> +/*
>> + * accepted syntax versions:
>
> "versions"?
s/versions/version
>
>> + * <low address>,<high address>,<type>
>> + * where low/high addresses are uint64_t in hexa (feat. 0x prefix)
>
> "hexa" is not a word.
OK
>
> I'm afraid I don't get the parenthesis.
I wanted to mention the 0x prefix was needed but as you mentionned below
it is not needed actually.
>
>> + * and type is an unsigned integer
>> + */
>> +static void get_interval(Object *obj, Visitor *v, const char *name,
>> + void *opaque, Error **errp)
>> +{
>> + DeviceState *dev = DEVICE(obj);
>> + Property *prop = opaque;
>> + Interval *interval = qdev_get_prop_ptr(dev, prop);
>> + char buffer[64];
>> + char *p = buffer;
>> +
>> + Snprintf(buffer, sizeof(buffer), "0x%"PRIx64",0x%"PRIx64",%d",
>> + interval->low, interval->high, interval->type);
>
> interval->type is unsigned. Use %u, not %d.
OK
>
>> +
>> + visit_type_str(v, name, &p, errp);
>> +}
>> +
>> +static void set_interval(Object *obj, Visitor *v, const char *name,
>> + void *opaque, Error **errp)
>> +{
>> + DeviceState *dev = DEVICE(obj);
>> + Property *prop = opaque;
>> + Interval *interval = qdev_get_prop_ptr(dev, prop);
>> + Error *local_err = NULL;
>> + unsigned int type;
>> + gchar **fields;
>> + uint64_t addr;
>> + char *str;
>> + int ret;
>> +
>> + if (dev->realized) {
>> + qdev_prop_set_after_realize(dev, name, errp);
>> + return;
>> + }
>> +
>> + visit_type_str(v, name, &str, &local_err);
>> + if (local_err) {
>> + error_propagate(errp, local_err);
>> + return;
>> + }
>> +
>> + fields = g_strsplit(str, ",", 3);
>> +
>> + ret = qemu_strtou64(fields[0], NULL, 16, &addr);
>
> Aha, the 0x prefix is actually optional.
>
>> + if (!ret) {
>> + interval->low = addr;
>> + } else {
>> + error_setg(errp, "Failed to decode interval low addr");
>> + error_append_hint(errp,
>> + "should be an address in hexa with 0x prefix\n");
>
> "hexa" is not a word, and the 0x prefix is actually optional.
OK
>
>> + goto out;
>> + }
>
> I prefer
>
> if (error) {
> handle error
> bail out
> }
> handle success
>
> over
>
> if (success) {
> handle success
> if (error) {
> handle error
> bail out
> }
>
> In this case:
>
> if (ret) {
> error_setg(errp, "Failed to decode interval low addr");
> error_append_hint(errp,
> "should be an address in hexa with 0x prefix\n");
> goto out;
> }
> interval->low = addr;
OK
>
>
>> +
>> + ret = qemu_strtou64(fields[1], NULL, 16, &addr);
>
> Crash if @str doesn't contain ',', because the g_strsplit(str, ",", 3)
> yields { [0] = str, NULL }.
>
>> + if (!ret) {
>> + interval->high = addr;
>> + } else {
>> + error_setg(errp, "Failed to decode interval high addr");
>> + error_append_hint(errp,
>> + "should be an address in hexa with 0x prefix\n");
>> + goto out;
>> + }
>> +
>> + ret = qemu_strtoui(fields[2], NULL, 10, &type);
>
> Likewise, crash if @str contains only one ','.
>
> I wouldn't use g_strsplit() here. After
>
> ret = qemu_strtoui(str, &endptr, 16, &interval->low);
>
> @endptr points behind the address. So:
>
> if (ret || *endptr != ',') {
> handle error ...
> goto out
> }
>
> ret = qemu_strtoui(endptr + 1, &endptr, 16, &interval->high);
>
> and so forth.
>
> Note that the if (ret || *endptr != ',') checks for two distinct errors.
> Distinct error messages might be more helpful.
OK I will revisit that.
>
>> + if (!ret) {
>> + interval->type = type;
>> + } else {
>> + error_setg(errp, "Failed to decode interval type");
>> + error_append_hint(errp, "should be an unsigned int in decimal\n");
>> + }
>> +out:
>> + g_free(str);
>> + g_strfreev(fields);
>> + return;
>> +}
>> +
>> +const PropertyInfo qdev_prop_interval = {
>> + .name = "labelled_interval",
>> + .description = "Labelled interval, example: 0xFEE00000,0xFEEFFFFF,0",
>> + .get = get_interval,
>> + .set = set_interval,
>> +};
>> +
>> /* --- on/off/auto --- */
>>
>> const PropertyInfo qdev_prop_on_off_auto = {
>> diff --git a/include/exec/memory.h b/include/exec/memory.h
>> index e499dc215b..e238d1c352 100644
>> --- a/include/exec/memory.h
>> +++ b/include/exec/memory.h
>> @@ -57,6 +57,12 @@ struct MemoryRegionMmio {
>> CPUWriteMemoryFunc *write[3];
>> };
>>
>> +struct Interval {
>> + hwaddr low;
>> + hwaddr high;
>> + unsigned int type;
>> +};
>
> This isn't an interval. An interval consists of two values, not three.
>
> The third one is called "type" here, and "label" elsewhere. Pick one
> and stick to it.
>
> Then pick a name for the triple. Elsewhere, you call it "labelled
> interval".
I would tend to use ReservedRegion now if nobody objects.
Thank you for the review!
Eric
>
>> +
>> typedef struct IOMMUTLBEntry IOMMUTLBEntry;
>>
>> /* See address_space_translate: bit 0 is read, bit 1 is write. */
>> diff --git a/include/hw/qdev-properties.h b/include/hw/qdev-properties.h
>> index c6a8cb5516..2ba7c8711b 100644
>> --- a/include/hw/qdev-properties.h
>> +++ b/include/hw/qdev-properties.h
>> @@ -20,6 +20,7 @@ extern const PropertyInfo qdev_prop_chr;
>> extern const PropertyInfo qdev_prop_tpm;
>> extern const PropertyInfo qdev_prop_ptr;
>> extern const PropertyInfo qdev_prop_macaddr;
>> +extern const PropertyInfo qdev_prop_interval;
>> extern const PropertyInfo qdev_prop_on_off_auto;
>> extern const PropertyInfo qdev_prop_losttickpolicy;
>> extern const PropertyInfo qdev_prop_blockdev_on_error;
>> @@ -202,6 +203,8 @@ extern const PropertyInfo qdev_prop_pcie_link_width;
>> DEFINE_PROP(_n, _s, _f, qdev_prop_drive_iothread, BlockBackend *)
>> #define DEFINE_PROP_MACADDR(_n, _s, _f) \
>> DEFINE_PROP(_n, _s, _f, qdev_prop_macaddr, MACAddr)
>> +#define DEFINE_PROP_INTERVAL(_n, _s, _f) \
>> + DEFINE_PROP(_n, _s, _f, qdev_prop_interval, Interval)
>> #define DEFINE_PROP_ON_OFF_AUTO(_n, _s, _f, _d) \
>> DEFINE_PROP_SIGNED(_n, _s, _f, _d, qdev_prop_on_off_auto, OnOffAuto)
>> #define DEFINE_PROP_LOSTTICKPOLICY(_n, _s, _f, _d) \
>> diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
>> index 375770a80f..a827c9a3fe 100644
>> --- a/include/qemu/typedefs.h
>> +++ b/include/qemu/typedefs.h
>> @@ -58,6 +58,7 @@ typedef struct ISABus ISABus;
>> typedef struct ISADevice ISADevice;
>> typedef struct IsaDma IsaDma;
>> typedef struct MACAddr MACAddr;
>> +typedef struct Interval Interval;
>> typedef struct MachineClass MachineClass;
>> typedef struct MachineState MachineState;
>> typedef struct MemoryListener MemoryListener;
>
>