On Tue, Jul 02, 2024 at 07:58:11PM +0000, Ashish Kalra wrote:
> +static bool make_pte_private(pte_t *pte, unsigned long addr, int pages, int level)
> +{
> + struct sev_es_runtime_data *data;
> + struct ghcb *ghcb;
> + int cpu;
> +
> + /*
> + * Ensure that all the per-cpu GHCBs are made private
> + * at the end of unshared loop so that we continue to use the
> + * optimized GHCB protocol and not force the switch to
> + * MSR protocol till the very end.
> + */
> + for_each_possible_cpu(cpu) {
> + data = per_cpu(runtime_data, cpu);
> + ghcb = &data->ghcb_page;
> + /* Check for GHCB for being part of a PMD range */
> + if ((unsigned long)ghcb >= addr &&
> + (unsigned long)ghcb <= (addr + (pages * PAGE_SIZE)))
> + return true;
> + }
> +
> + set_pte_enc(pte, level, (void *)addr);
> + snp_set_memory_private(addr, pages);
> +
> + return true;
Zap make_pte_private()
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index f263ceada006..65234ffb1495 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -1022,39 +1022,14 @@ static void set_pte_enc(pte_t *kpte, int level, void *va)
set_pte_enc_mask(kpte, d.pfn, d.new_pgprot);
}
-static bool make_pte_private(pte_t *pte, unsigned long addr, int pages, int level)
-{
- struct sev_es_runtime_data *data;
- struct ghcb *ghcb;
- int cpu;
-
- /*
- * Ensure that all the per-cpu GHCBs are made private
- * at the end of unshared loop so that we continue to use the
- * optimized GHCB protocol and not force the switch to
- * MSR protocol till the very end.
- */
- for_each_possible_cpu(cpu) {
- data = per_cpu(runtime_data, cpu);
- ghcb = &data->ghcb_page;
- /* Check for GHCB for being part of a PMD range */
- if ((unsigned long)ghcb >= addr &&
- (unsigned long)ghcb <= (addr + (pages * PAGE_SIZE)))
- return true;
- }
-
- set_pte_enc(pte, level, (void *)addr);
- snp_set_memory_private(addr, pages);
-
- return true;
-}
-
/* Walk the direct mapping and convert all shared memory back to private. */
static void unshare_all_memory(void)
{
- unsigned long addr, end, size;
+ unsigned long addr, end, size, ghcb;
+ struct sev_es_runtime_data *data;
unsigned int npages, level;
pte_t *pte;
+ int cpu;
/* Unshare the direct mapping. */
addr = PAGE_OFFSET;
@@ -1063,17 +1038,28 @@ static void unshare_all_memory(void)
while (addr < end) {
pte = lookup_address(addr, &level);
size = page_level_size(level);
+ npages = size / PAGE_SIZE;
if (!pte || !pte_decrypted(*pte) || pte_none(*pte)) {
addr += size;
continue;
}
- npages = size / PAGE_SIZE;
+ /*
+ * Ensure that all the per-cpu GHCBs are made private at the
+ * end of unsharing loop so that the switch to the slower MSR
+ * protocol happens last.
+ */
+ for_each_possible_cpu(cpu) {
+ data = per_cpu(runtime_data, cpu);
+ ghcb = (unsigned long)&data->ghcb_page;
+
+ if (addr <= ghcb && ghcb <= addr + size)
+ continue;
+ }
- if (!make_pte_private(pte, addr, npages, level))
- pr_err("Failed to unshare range %#lx-%#lx\n",
- addr, addr + size);
+ set_pte_enc(pte, level, (void *)addr);
+ snp_set_memory_private(addr, npages);
}
/* Unshare all bss decrypted memory. */
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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