> +int psmash(struct page *page)
> +{
> + unsigned long spa = page_to_pfn(page) << PAGE_SHIFT;
> + int ret;
> +
> + if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
> + return -ENXIO;
> +
> + /* Retry if another processor is modifying the RMP entry. */
> + do {
> + /* Binutils version 2.36 supports the PSMASH mnemonic. */
> + asm volatile(".byte 0xF3, 0x0F, 0x01, 0xFF"
> + : "=a"(ret)
> + : "a"(spa)
> + : "memory", "cc");
> + } while (ret == FAIL_INUSE);
Should there be some retry limit here for safety? Or do we know that
we'll never be stuck in this loop? Ditto for the loop in rmpupdate.
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(psmash);
>
