From: Eric Auger <eric.auger@redhat.com>
To: Gavin Shan <gshan@redhat.com>, qemu-arm@nongnu.org
Cc: qemu-devel@nongnu.org, maz@kernel.org, cohuck@redhat.com,
richard.henderson@linaro.org, peter.maydell@linaro.org,
zhenyzha@redhat.com, shan.gavin@gmail.com
Subject: Re: [PATCH v7 7/7] hw/arm/virt: Add properties to disable high memory regions
Date: Thu, 3 Nov 2022 11:12:44 +0100 [thread overview]
Message-ID: <fc877215-61dc-8c9a-fb0e-5ffa000cef07@redhat.com> (raw)
In-Reply-To: <20221029224307.138822-8-gshan@redhat.com>
Hi Gavin,
On 10/30/22 00:43, Gavin Shan wrote:
> The 3 high memory regions are usually enabled by default, but they may
> be not used. For example, VIRT_HIGH_GIC_REDIST2 isn't needed by GICv2.
> This leads to waste in the PA space.
>
> Add properties ("highmem-redists", "highmem-ecam", "highmem-mmio") to
> allow users selectively disable them if needed. After that, the high
> memory region for GICv3 or GICv4 redistributor can be disabled by user,
> the number of maximal supported CPUs needs to be calculated based on
> 'vms->highmem_redists'. The follow-up error message is also improved
> to indicate if the high memory region for GICv3 and GICv4 has been
> enabled or not.
>
> Suggested-by: Marc Zyngier <maz@kernel.org>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> Reviewed-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Thanks
Eric
> ---
> docs/system/arm/virt.rst | 13 +++++++
> hw/arm/virt.c | 75 ++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 86 insertions(+), 2 deletions(-)
>
> diff --git a/docs/system/arm/virt.rst b/docs/system/arm/virt.rst
> index 4454706392..188a4f211f 100644
> --- a/docs/system/arm/virt.rst
> +++ b/docs/system/arm/virt.rst
> @@ -98,6 +98,19 @@ compact-highmem
> Set ``on``/``off`` to enable/disable the compact layout for high memory regions.
> The default is ``on`` for machine types later than ``virt-7.2``.
>
> +highmem-redists
> + Set ``on``/``off`` to enable/disable the high memory region for GICv3 or
> + GICv4 redistributor. The default is ``on``. Setting this to ``off`` will
> + limit the maximum number of CPUs when GICv3 or GICv4 is used.
> +
> +highmem-ecam
> + Set ``on``/``off`` to enable/disable the high memory region for PCI ECAM.
> + The default is ``on`` for machine types later than ``virt-3.0``.
> +
> +highmem-mmio
> + Set ``on``/``off`` to enable/disable the high memory region for PCI MMIO.
> + The default is ``on``.
> +
> gic-version
> Specify the version of the Generic Interrupt Controller (GIC) to provide.
> Valid values are:
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 020a95cfa2..65cff7add1 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2095,14 +2095,20 @@ static void machvirt_init(MachineState *machine)
> if (vms->gic_version == VIRT_GIC_VERSION_2) {
> virt_max_cpus = GIC_NCPU;
> } else {
> - virt_max_cpus = virt_redist_capacity(vms, VIRT_GIC_REDIST) +
> - virt_redist_capacity(vms, VIRT_HIGH_GIC_REDIST2);
> + virt_max_cpus = virt_redist_capacity(vms, VIRT_GIC_REDIST);
> + if (vms->highmem_redists) {
> + virt_max_cpus += virt_redist_capacity(vms, VIRT_HIGH_GIC_REDIST2);
> + }
> }
>
> if (max_cpus > virt_max_cpus) {
> error_report("Number of SMP CPUs requested (%d) exceeds max CPUs "
> "supported by machine 'mach-virt' (%d)",
> max_cpus, virt_max_cpus);
> + if (vms->gic_version != VIRT_GIC_VERSION_2 && !vms->highmem_redists) {
> + error_printf("Try 'highmem-redists=on' for more CPUs\n");
> + }
> +
> exit(1);
> }
>
> @@ -2371,6 +2377,49 @@ static void virt_set_compact_highmem(Object *obj, bool value, Error **errp)
> vms->highmem_compact = value;
> }
>
> +static bool virt_get_highmem_redists(Object *obj, Error **errp)
> +{
> + VirtMachineState *vms = VIRT_MACHINE(obj);
> +
> + return vms->highmem_redists;
> +}
> +
> +static void virt_set_highmem_redists(Object *obj, bool value, Error **errp)
> +{
> + VirtMachineState *vms = VIRT_MACHINE(obj);
> +
> + vms->highmem_redists = value;
> +}
> +
> +static bool virt_get_highmem_ecam(Object *obj, Error **errp)
> +{
> + VirtMachineState *vms = VIRT_MACHINE(obj);
> +
> + return vms->highmem_ecam;
> +}
> +
> +static void virt_set_highmem_ecam(Object *obj, bool value, Error **errp)
> +{
> + VirtMachineState *vms = VIRT_MACHINE(obj);
> +
> + vms->highmem_ecam = value;
> +}
> +
> +static bool virt_get_highmem_mmio(Object *obj, Error **errp)
> +{
> + VirtMachineState *vms = VIRT_MACHINE(obj);
> +
> + return vms->highmem_mmio;
> +}
> +
> +static void virt_set_highmem_mmio(Object *obj, bool value, Error **errp)
> +{
> + VirtMachineState *vms = VIRT_MACHINE(obj);
> +
> + vms->highmem_mmio = value;
> +}
> +
> +
> static bool virt_get_its(Object *obj, Error **errp)
> {
> VirtMachineState *vms = VIRT_MACHINE(obj);
> @@ -2996,6 +3045,28 @@ static void virt_machine_class_init(ObjectClass *oc, void *data)
> "Set on/off to enable/disable compact "
> "layout for high memory regions");
>
> + object_class_property_add_bool(oc, "highmem-redists",
> + virt_get_highmem_redists,
> + virt_set_highmem_redists);
> + object_class_property_set_description(oc, "highmem-redists",
> + "Set on/off to enable/disable high "
> + "memory region for GICv3 or GICv4 "
> + "redistributor");
> +
> + object_class_property_add_bool(oc, "highmem-ecam",
> + virt_get_highmem_ecam,
> + virt_set_highmem_ecam);
> + object_class_property_set_description(oc, "highmem-ecam",
> + "Set on/off to enable/disable high "
> + "memory region for PCI ECAM");
> +
> + object_class_property_add_bool(oc, "highmem-mmio",
> + virt_get_highmem_mmio,
> + virt_set_highmem_mmio);
> + object_class_property_set_description(oc, "highmem-mmio",
> + "Set on/off to enable/disable high "
> + "memory region for PCI MMIO");
> +
> object_class_property_add_str(oc, "gic-version", virt_get_gic_version,
> virt_set_gic_version);
> object_class_property_set_description(oc, "gic-version",
next prev parent reply other threads:[~2022-11-03 10:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-29 22:43 [PATCH v7 0/7] hw/arm/virt: Improve address assignment for high memory regions Gavin Shan
2022-10-29 22:43 ` [PATCH v7 1/7] hw/arm/virt: Introduce virt_set_high_memmap() helper Gavin Shan
2022-10-29 22:43 ` [PATCH v7 2/7] hw/arm/virt: Rename variable size to region_size in virt_set_high_memmap() Gavin Shan
2022-10-29 22:43 ` [PATCH v7 3/7] hw/arm/virt: Introduce variable region_base " Gavin Shan
2022-10-29 22:43 ` [PATCH v7 4/7] hw/arm/virt: Introduce virt_get_high_memmap_enabled() helper Gavin Shan
2022-10-29 22:43 ` [PATCH v7 5/7] hw/arm/virt: Improve high memory region address assignment Gavin Shan
2022-10-29 22:43 ` [PATCH v7 6/7] hw/arm/virt: Add 'compact-highmem' property Gavin Shan
2022-10-29 22:43 ` [PATCH v7 7/7] hw/arm/virt: Add properties to disable high memory regions Gavin Shan
2022-11-02 8:57 ` Cornelia Huck
2022-11-03 10:12 ` Eric Auger [this message]
2022-11-21 17:16 ` [PATCH v7 0/7] hw/arm/virt: Improve address assignment for " Peter Maydell
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