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Re: [PATCH 0/8] Simplify memory_region_add_subregion_overlap(..., priori
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From: |
Michael S. Tsirkin |
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Subject: |
Re: [PATCH 0/8] Simplify memory_region_add_subregion_overlap(..., priority=0) |
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Date: |
Sun, 15 Dec 2019 04:54:42 -0500 |
On Sat, Dec 14, 2019 at 08:01:46PM +0000, Peter Maydell wrote:
> On Sat, 14 Dec 2019 at 18:17, Philippe Mathieu-Daudé <address@hidden> wrote:
> > Maybe we can a warning if priority=0, to force board designers to use
> > explicit priority (explicit overlap).
>
> Priority 0 is fine, it's just one of the possible positive and
> negative values. I think what ideally we would complain about
> is where we see an overlap and both the regions involved
> have the same priority value, because in that case which
> one the guest sees is implicitly dependent on (I think) which
> order the subregions were added, which is fragile if we move
> code around. I'm not sure how easy that is to test for or how
> much of our existing code violates it, though.
>
> thanks
> -- PMM
Problem is it's not uncommon for guests to create such
configs, and then just never access them.
So the thing to do would be to complain *on access*.
--
MST
- [PATCH 1/8] hw/arm/nrf51_soc: Use memory_region_add_subregion() when priority is 0, (continued)
- [PATCH 1/8] hw/arm/nrf51_soc: Use memory_region_add_subregion() when priority is 0, Philippe Mathieu-Daudé, 2019/12/14
- [PATCH 3/8] hw/arm/xlnx-versal: Use memory_region_add_subregion() when priority is 0, Philippe Mathieu-Daudé, 2019/12/14
- [PATCH 2/8] hw/arm/raspi: Use memory_region_add_subregion() when priority is 0, Philippe Mathieu-Daudé, 2019/12/14
- [PATCH 6/8] hw/vfio/pci: Use memory_region_add_subregion() when priority is 0, Philippe Mathieu-Daudé, 2019/12/14
- [PATCH 5/8] hw/mips/boston: Use memory_region_add_subregion() when priority is 0, Philippe Mathieu-Daudé, 2019/12/14
- [PATCH 7/8] target/i386: Use memory_region_add_subregion() when priority is 0, Philippe Mathieu-Daudé, 2019/12/14
- [PATCH 4/8] hw/i386/intel_iommu: Use memory_region_add_subregion when priority is 0, Philippe Mathieu-Daudé, 2019/12/14
- Re: [PATCH 0/8] Simplify memory_region_add_subregion_overlap(..., priority=0), Peter Maydell, 2019/12/14
- Re: [PATCH 0/8] Simplify memory_region_add_subregion_overlap(..., priority=0), Michael S. Tsirkin, 2019/12/15