Hi Marc,
On 12/27/21 4:53 PM, Marc Zyngier wrote:
> Hi Eric,
>
> Picking this up again after a stupidly long time...
>
> On Mon, 04 Oct 2021 13:00:21 +0100,
> Eric Auger <eric.auger@xxxxxxxxxx> wrote:
>> Hi Marc,
>>
>> On 10/3/21 6:46 PM, Marc Zyngier wrote:
>>> Currently, the highmem PCIe region is oddly keyed on the highmem
>>> attribute instead of highmem_ecam. Move the enablement of this PCIe
>>> region over to highmem_ecam.
>>>
>>> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
>>> ---
>>> hw/arm/virt-acpi-build.c | 10 ++++------
>>> hw/arm/virt.c | 4 ++--
>>> 2 files changed, 6 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
>>> index 037cc1fd82..d7bef0e627 100644
>>> --- a/hw/arm/virt-acpi-build.c
>>> +++ b/hw/arm/virt-acpi-build.c
>>> @@ -157,10 +157,9 @@ static void acpi_dsdt_add_virtio(Aml *scope,
>>> }
>>>
>>> static void acpi_dsdt_add_pci(Aml *scope, const MemMapEntry *memmap,
>>> - uint32_t irq, bool use_highmem, bool highmem_ecam,
>>> - VirtMachineState *vms)
>>> + uint32_t irq, VirtMachineState *vms)
>>> {
>>> - int ecam_id = VIRT_ECAM_ID(highmem_ecam);
>>> + int ecam_id = VIRT_ECAM_ID(vms->highmem_ecam);
>>> struct GPEXConfig cfg = {
>>> .mmio32 = memmap[VIRT_PCIE_MMIO],
>>> .pio = memmap[VIRT_PCIE_PIO],
>>> @@ -169,7 +168,7 @@ static void acpi_dsdt_add_pci(Aml *scope, const MemMapEntry *memmap,
>>> .bus = vms->bus,
>>> };
>>>
>>> - if (use_highmem) {
>>> + if (vms->highmem_ecam) {
>> highmem_ecam is more restrictive than use_highmem:
>> vms->highmem_ecam &= vms->highmem && (!firmware_loaded || aarch64);
>>
>> If I remember correctly there was a problem using highmem ECAM with 32b
>> AAVMF FW.
>>
>> However 5125f9cd2532 ("hw/arm/virt: Add high MMIO PCI region, 512G in
>> size") introduced high MMIO PCI region without this constraint.
> Then I really don't understand the point of this highmem_ecam. We only
> register the highmem version if highmem_ecam is set (see the use of
> VIRT_ECAM_ID() to pick the right ECAM window).
but aren't we talking about different regions? On one hand the [high]
MMIO region (512GB wide) and the [high] ECAM region (256MB large).
To me you can enable either independently. High MMIO region is used by
some devices likes ivshmem/video cards while high ECAM was introduced to
extend the number of supported buses: 601d626d148a (hw/arm/virt: Add a
new 256MB ECAM region).
with the above change the high MMIO region won't be set with 32b
FW+kernel and LPAE whereas it is currently.
high ECAM was not supported by 32b FW, hence the highmem_ecam.
but maybe I miss your point?
Eric
>
> So keying this on highmem makes it expose a device that may not be
> there the first place since, as you pointed out that highmem_ecam can
> be false in cases where highmem is true.
>
>> So to me we should keep vms->highmem here
> I really must be missing how this is supposed to work.
>
> M.
>
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