Re: [PATCHv5 29/30] ACPICA: Avoid cache flush inside virtual machines

[Dan Williams]

On Wed, Mar 2, 2022 at 6:28 AM Kirill A. Shutemov
<kirill.shutemov@xxxxxxxxxxxxxxx> wrote:
>
> WBINVD is not supported in TDX guest and triggers #VE. There's no robust
> way to emulate it. The kernel has to avoid it.
>
> ACPI_FLUSH_CPU_CACHE() flushes caches usign WBINVD on entering sleep
> states. It is required to prevent data loss.
>
> While running inside virtual machine, the kernel can bypass cache
> flushing. Changing sleep state in a virtual machine doesn't affect the
> host system sleep state and cannot lead to data loss.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>

Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>