[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v3 1/5] qdev: Introduce DEFINE_PROP_RESERVED_REGION
From: |
Markus Armbruster |
Subject: |
Re: [PATCH v3 1/5] qdev: Introduce DEFINE_PROP_RESERVED_REGION |
Date: |
Mon, 22 Jun 2020 13:22:46 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) |
Eric Auger <eric.auger@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.auger@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);
> +
> + 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.
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);
No need to mess around with error_append_hint() then.
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.fsf@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.
> + 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 <armbru@redhat.com>
[PATCH v3 2/5] virtio-iommu: Implement RESV_MEM probe request, Eric Auger, 2020/06/11
[PATCH v3 3/5] virtio-iommu: Handle reserved regions in the translation process, Eric Auger, 2020/06/11
[PATCH v3 4/5] virtio-iommu-pci: Add array of Interval properties, Eric Auger, 2020/06/11