Hi Gavin,
On 10/24/22 05:54, 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 likely to be disabled by
> code 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, high_memmap}() isn't
> optimized because the high memory region's PA space is always reserved,
> regardless of whatever the actual state in the corresponding
> vms->highmem_{redists, ecam, mmio} flag. In the code, 'base' and
> 'vms->highest_gpa' are always increased for case (1), (2) and (3).
> It's unnecessary since the assigned PA space for the disabled high
> memory region won't be used afterwards.
>
> Improve 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). The memory layout may
> be changed after the improvement is applied, which leads to potential
> migration breakage. So 'vms->highmem_compact' is added to control if
> the improvement should be applied. For now, 'vms->highmem_compact' is
> set to false, meaning that we don't have memory layout change until it
> becomes configurable through property 'compact-highmem' in next patch.
>
> Signed-off-by: Gavin Shan <gs...@redhat.com>
> Reviewed-by: Cornelia Huck <coh...@redhat.com>
the code has quite changed since Connie's R-b
> Tested-by: Zhenyu Zhang <zheny...@redhat.com>
> ---
> hw/arm/virt.c | 15 ++++++++++-----
> include/hw/arm/virt.h | 1 +
> 2 files changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index ee98a8a3b6..4896f600b4 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -1721,18 +1721,23 @@ static void virt_set_high_memmap(VirtMachineState
> *vms,
> vms->memmap[i].size = region_size;
>
> /*
> - * Check each device to see if they fit in the PA space,
> - * moving highest_gpa as we go.
> + * Check each device to see if it fits in the PA space,
> + * moving highest_gpa as we go. For compatibility, move
> + * highest_gpa for disabled fitting devices as well, if
> + * the compact layout has been disabled.
> *
> * 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;
> + *region_enabled &= fits;
> + if (vms->highmem_compact && !*region_enabled) {
> + continue;
> }
>
> - *region_enabled &= fits;
> base = region_base + region_size;
> + if (fits) {
> + vms->highest_gpa = region_base + region_size - 1;
vms->highest_gpa = base - 1;
> + }
> }
> }
>
> diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
> index 6ec479ca2b..709f623741 100644
> --- a/include/hw/arm/virt.h
> +++ b/include/hw/arm/virt.h
> @@ -144,6 +144,7 @@ struct VirtMachineState {
> PFlashCFI01 *flash[2];
> bool secure;
> bool highmem;
> + bool highmem_compact;
> bool highmem_ecam;
> bool highmem_mmio;
> bool highmem_redists;
Besides
Reviewed-by: Eric Auger <eric.au...@redhat.com>
Thanks
Eric
