[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v3 4/5] hw/arm/virt: Improve high memory region address assig
From: |
Eric Auger |
Subject: |
Re: [PATCH v3 4/5] hw/arm/virt: Improve high memory region address assignment |
Date: |
Wed, 28 Sep 2022 14:51:38 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 |
Hi Gavin,
On 9/22/22 01:13, Gavin Shan wrote:
> There are three high memory regions, which are VIRT_HIGH_REDIST2,
> VIRT_HIGH_PCIE_ECAM and VIRT_HIGH_PCIE_MMIO. Their base addresses
> are floating on highest RAM address. However, they can be disabled
> in several cases.
>
> (1) One specific high memory region is disabled by developer by
> toggling vms->highmem_{redists, ecam, mmio}.
>
> (2) VIRT_HIGH_PCIE_ECAM region is disabled on machine, which is
> 'virt-2.12' or ealier than it.
>
> (3) VIRT_HIGH_PCIE_ECAM region is disabled when firmware is loaded
> on 32-bits system.
>
> (4) One specific high memory region is disabled when it breaks the
> PA space limit.
>
> The current implementation of virt_set_memmap() isn't comprehensive
> because the space for one specific high memory region is always
> reserved from the PA space for case (1), (2) and (3). In the code,
> 'base' and 'vms->highest_gpa' are always increased for those three
> cases. It's unnecessary since the assigned space of the disabled
> high memory region won't be used afterwards.
>
> This improves the address assignment for those three high memory
> region by skipping the address assignment for one specific high
> memory region if it has been disabled in case (1), (2) and (3).
>
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
> hw/arm/virt.c | 44 ++++++++++++++++++++++++++------------------
> 1 file changed, 26 insertions(+), 18 deletions(-)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index b0b679d1f4..b702f8f2b5 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -1693,15 +1693,31 @@ static void virt_set_high_memmap(VirtMachineState
> *vms,
> hwaddr base, int pa_bits)
> {
> hwaddr region_base, region_size;
> - bool fits;
> + bool *region_enabled, fits;
IDo you really need a pointer? If the region is unknown this is a bug in
virt code.
> int i;
>
> for (i = VIRT_LOWMEMMAP_LAST; i < ARRAY_SIZE(extended_memmap); i++) {
> region_base = ROUND_UP(base, extended_memmap[i].size);
> region_size = extended_memmap[i].size;
>
> - vms->memmap[i].base = region_base;
> - vms->memmap[i].size = region_size;
> + switch (i) {
> + case VIRT_HIGH_GIC_REDIST2:
> + region_enabled = &vms->highmem_redists;
> + break;
> + case VIRT_HIGH_PCIE_ECAM:
> + region_enabled = &vms->highmem_ecam;
> + break;
> + case VIRT_HIGH_PCIE_MMIO:
> + region_enabled = &vms->highmem_mmio;
> + break;
While we are at it I would change the vms fields dealing with those
highmem regions and turn those fields into an array of bool indexed
using i - VIRT_LOWMEMMAP_LAST (using a macro or something alike). We
would not be obliged to have this switch, now duplicated.
> + default:
> + region_enabled = NULL;
> + }
> +
> + /* Skip unknown region */
> + if (!region_enabled) {
> + continue;
> + }
>
> /*
> * Check each device to see if they fit in the PA space,
> @@ -1710,23 +1726,15 @@ static void virt_set_high_memmap(VirtMachineState
> *vms,
> * For each device that doesn't fit, disable it.
> */
> fits = (region_base + region_size) <= BIT_ULL(pa_bits);
> - if (fits) {
> - vms->highest_gpa = region_base + region_size - 1;
> - }
> + if (*region_enabled && fits) {
> + vms->memmap[i].base = region_base;
> + vms->memmap[i].size = region_size;
>
> - switch (i) {
> - case VIRT_HIGH_GIC_REDIST2:
> - vms->highmem_redists &= fits;
> - break;
> - case VIRT_HIGH_PCIE_ECAM:
> - vms->highmem_ecam &= fits;
> - break;
> - case VIRT_HIGH_PCIE_MMIO:
> - vms->highmem_mmio &= fits;
> - break;
> + vms->highest_gpa = region_base + region_size - 1;
> + base = region_base + region_size;
> + } else {
> + *region_enabled = false;
> }
> -
> - base = region_base + region_size;
> }
> }
>
Thanks
Eric
- [PATCH v3 0/5] hw/arm/virt: Improve address assignment for high memory regions, Gavin Shan, 2022/09/21
- [PATCH v3 1/5] hw/arm/virt: Introduce virt_set_high_memmap() helper, Gavin Shan, 2022/09/21
- [PATCH v3 2/5] hw/arm/virt: Rename variable size to region_size in virt_set_high_memmap(), Gavin Shan, 2022/09/21
- [PATCH v3 4/5] hw/arm/virt: Improve high memory region address assignment, Gavin Shan, 2022/09/21
- Re: [PATCH v3 4/5] hw/arm/virt: Improve high memory region address assignment,
Eric Auger <=
- [PATCH v3 5/5] hw/arm/virt: Add 'highmem-compact' property, Gavin Shan, 2022/09/21
- [PATCH v3 3/5] hw/arm/virt: Introduce variable region_base in virt_set_high_memmap(), Gavin Shan, 2022/09/21
- Re: [PATCH v3 0/5] hw/arm/virt: Improve address assignment for high memory regions, Zhenyu Zhang, 2022/09/21