Hi Markus,
On 6/22/20 1:22 PM, Markus Armbruster wrote:
> Eric Auger <eric.au...@redhat.com> writes:
>
>> Introduce a new property defining a reserved region:
>> <low address>, <high address>, <type>.
>>
>> This will be used to encode reserved IOVA regions.
>>
>> 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 type of the reserved region
>> will match the virtio_iommu_probe_resv_mem subtype value:
>> - VIRTIO_IOMMU_RESV_MEM_T_RESERVED (0)
>> - VIRTIO_IOMMU_RESV_MEM_T_MSI (1)
>>
>> on PC/Q35 machine, this will be used to inform the
>> virtio-iommu-pci device it should bypass the MSI region.
>> The reserved region will be: 0xfee00000, 0xfeefffff, 1.
>>
>> On ARM, we can declare the ITS MSI doorbell as an MSI
>> region to prevent MSIs from being mapped on guest side.
>>
>> Signed-off-by: Eric Auger <eric.au...@redhat.com>
>>
>> ---
>>
>> v11 -> v12:
>> - rename into DEFINE_PROP_RESERVED_REGION
>> - do not use g_strsplit anymore, use endptr instead
>> - remove 0x references
>> ---
>> include/exec/memory.h | 6 +++
>> include/hw/qdev-properties.h | 3 ++
>> include/qemu/typedefs.h | 1 +
>> hw/core/qdev-properties.c | 89 ++++++++++++++++++++++++++++++++++++
>> 4 files changed, 99 insertions(+)
>>
>> diff --git a/include/exec/memory.h b/include/exec/memory.h
>> index 3e00cdbbfa..3ee8224fa7 100644
>> --- a/include/exec/memory.h
>> +++ b/include/exec/memory.h
>> @@ -57,6 +57,12 @@ struct MemoryRegionMmio {
>> CPUWriteMemoryFunc *write[3];
>> };
>>
>> +struct ReservedRegion {
>> + hwaddr low;
>> + hwaddr high;
>> + unsigned int type;
>> +};
>> +
>> 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 f161604fb6..03bf850a7e 100644
>> --- a/include/hw/qdev-properties.h
>> +++ b/include/hw/qdev-properties.h
>> @@ -19,6 +19,7 @@ extern const PropertyInfo qdev_prop_string;
>> extern const PropertyInfo qdev_prop_chr;
>> extern const PropertyInfo qdev_prop_tpm;
>> extern const PropertyInfo qdev_prop_macaddr;
>> +extern const PropertyInfo qdev_prop_reserved_region;
>> extern const PropertyInfo qdev_prop_on_off_auto;
>> extern const PropertyInfo qdev_prop_multifd_compression;
>> extern const PropertyInfo qdev_prop_losttickpolicy;
>> @@ -183,6 +184,8 @@ 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_RESERVED_REGION(_n, _s, _f) \
>> + DEFINE_PROP(_n, _s, _f, qdev_prop_reserved_region, ReservedRegion)
>> #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_MULTIFD_COMPRESSION(_n, _s, _f, _d) \
>> diff --git a/include/qemu/typedefs.h b/include/qemu/typedefs.h
>> index ecf3cde26c..85c4f891f4 100644
>> --- a/include/qemu/typedefs.h
>> +++ b/include/qemu/typedefs.h
>> @@ -59,6 +59,7 @@ typedef struct ISABus ISABus;
>> typedef struct ISADevice ISADevice;
>> typedef struct IsaDma IsaDma;
>> typedef struct MACAddr MACAddr;
>> +typedef struct ReservedRegion ReservedRegion;
>> typedef struct MachineClass MachineClass;
>> typedef struct MachineState MachineState;
>> typedef struct MemoryListener MemoryListener;
>> diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
>> index cc924815da..15b84adbee 100644
>> --- a/hw/core/qdev-properties.c
>> +++ b/hw/core/qdev-properties.c
>> @@ -14,6 +14,7 @@
>> #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)
>> @@ -577,6 +578,94 @@ const PropertyInfo qdev_prop_macaddr = {
>> .set = set_mac,
>> };
>>
>> +/* --- Reserved Region --- */
>> +
>> +/*
>> + * accepted syntax version:
>> + * <low address>,<high address>,<type>
>> + * where low/high addresses are uint64_t in hexadecimal
>> + * and type is an unsigned integer in decimal
>> + */
>> +static void get_reserved_region(Object *obj, Visitor *v, const char *name,
>> + void *opaque, Error **errp)
>> +{
>> + DeviceState *dev = DEVICE(obj);
>> + Property *prop = opaque;
>> + ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
>> + char buffer[64];
>> + char *p = buffer;
>> +
>> + snprintf(buffer, sizeof(buffer), "0x%"PRIx64",0x%"PRIx64",%u",
>> + rr->low, rr->high, rr->type);
>
> Matches existing practice in other getters. Nevertheless, I'd suggest
> something like
>
> n = snprintf(buffer, sizeof(buffer), ...);
> assert(n < sizeof(buffer);
OK
>
>> +
>> + visit_type_str(v, name, &p, errp);
>> +}
>> +
>> +static void set_reserved_region(Object *obj, Visitor *v, const char *name,
>> + void *opaque, Error **errp)
>> +{
>> + DeviceState *dev = DEVICE(obj);
>> + Property *prop = opaque;
>> + ReservedRegion *rr = qdev_get_prop_ptr(dev, prop);
>> + Error *local_err = NULL;
>> + const char *endptr;
>> + 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;
>> + }
>> +
>> + ret = qemu_strtou64(str, &endptr, 16, &rr->low);
>> + if (ret) {
>> + error_setg(errp, "Failed to decode reserved region low addr");
>> + error_append_hint(errp,
>> + "should be an address in hexadecimal\n");
>
> Comes out like this:
>
> qemu-system-x86_64: -device ...: Failed to decode reserved region low addr
> should be an address in hexadecimal
>
> I'd capitalize the other way, to get
>
> qemu-system-x86_64: -device ...: failed to decode reserved region low addr
> Should be an address in hexadecimal
>
> Note: output is made up; I failed at figuring out how to use the new
> property. An example in PATCH 4's commit message might help.
OK I will add one example. In practice in the virtio-iommu case the
property is not really meant to be passed by the end-user but should be
set by the machine code. However I have just tested from the cmd line
and it looks using commas as separators is a bad idea because it
collides with ',' separating properties. So if you're OK I will change
the comma into ':'.
>
> Since the error message fails to mention @name, the user is left
> guessing unless "-device ..." contains just one reserved region
> parameter.
>
> What about something like this:
>
> error_setg(errp, "start address of reserved region '%s'"
> " must be a hexadecimal integer",
> name);
Sure. Given the fact the property is named reserved-region[n], this may
be simplified into
error_setg(errp, "start address of '%s'"
" must be a hexadecimal integer",
> name);
>
> No need to mess around with error_append_hint() then.
OK
>
> Same for the other error messages.
>
>> + goto out;
>> + }
>> + if (*endptr != ',') {
>> + goto separator_error;
>> + }
>> +
>> + ret = qemu_strtou64(endptr + 1, &endptr, 16, &rr->high);
>> + if (ret) {
>> + error_setg(errp, "Failed to decode reserved region high addr");
>> + error_append_hint(errp,
>> + "should be an address in hexadecimal\n");
>> + goto out;
>> + }
>> + if (*endptr != ',') {
>> + goto separator_error;
>> + }
>> +
>> + ret = qemu_strtoui(endptr + 1, &endptr, 10, &rr->type);
>> + if (ret) {
>> + error_setg(errp, "Failed to decode reserved region type");
>> + error_append_hint(errp, "should be an unsigned integer in
>> decimal\n");
>> + }
>
> I dimly remember discussing the wisdom of numeric type here, dig, dig,
> ..., aha:
>
> Subject: Re: [PATCH for-5.0 v11 12/20] qapi: Introduce
> DEFINE_PROP_INTERVAL
> Date: Fri, 13 Dec 2019 11:03:02 +0100
> Message-ID: <87y2vg4k6h....@dusky.pond.sub.org>
>
> >> 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?
>
> I'd prioritize the user interface over possible reuse (which might never
> happen). Mind, I'm not telling you using numbers is a bad user
> interface. In general, enums are nicer, but I don't know enough about
> this particular case.
Yep I remember too ;-) I left as it was because I think this property
could be used for other use cases.
>
>> + goto out;
>> +
>> +separator_error:
>> + error_setg(errp, "reserved region fields must be separated with
>> commas");
>
> I'm not sure de-duplicating this error message is worth the extra goto.
>
>> +out:
>> + g_free(str);
>> + return;
>> +}
>> +
>> +const PropertyInfo qdev_prop_reserved_region = {
>> + .name = "reserved_region",
>> + .description = "Reserved Region, example: 0xFEE00000,0xFEEFFFFF,0",
>> + .get = get_reserved_region,
>> + .set = set_reserved_region,
>> +};
>> +
>> /* --- on/off/auto --- */
>>
>> const PropertyInfo qdev_prop_on_off_auto = {
>
> Can't find anything that's actually wrong, so
>
> Reviewed-by: Markus Armbruster <arm...@redhat.com>
Thanks
Eric
>
