Re: [PATCH 0/6] Add RMPOPT support.

[Dave Hansen]

On 2/17/26 20:12, Kalra, Ashish wrote:
>> That's not awful.
>>
>> To be honest, though, I think this is misdesigned. Shouldn't the CPU
>> *boot* in a state where it is optimized? Why should software have to
>> tell it that coming out of reset, there is no SEV-SNP memory?
> When the CPU boots, the RMP checks are not done and therefore the CPU
> is booting in a state where it is optimized.
> 
> The RMP checks are not enabled till SEV-SNP is enabled and SNP is enabled
> during kernel boot (as part of iommu_snp_enable() -> snp_rmptable_init()).
> 
> Once SNP is enabled as part of kernel boot, hypervisor and non-SNP guests are
> subject to RMP checks on writes to provide integrity of SEV-SNP guest memory.
> 
> Therefore, we need to enable these RMP optimizations after SNP has been 
> enabled to indicate which 1GB regions of memory are known to not contain any
> SEV-SNP guest memory.

They are known not to contain any SEV-SNP guest memory at the moment
snp_rmptable_init() finishes, no?