powerpc/mm/book3s64/radix: Off-load TLB invalidations to host when !GTSE

When platform doesn't support GTSE, let TLB invalidation requests
for radix guests be off-loaded to the host using H_RPT_INVALIDATE
hcall.

	[hcall wrapper, error path handling and renames]

Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Bharata B Rao <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

1 files changed, 52 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/plpar_wrappers.h b/arch/powerpc/include/asm/plpar_wrappers.h
index 4497c8afb573..4293c5d2ddf4 100644
--- a/arch/powerpc/include/asm/plpar_wrappers.h
+++ b/arch/powerpc/include/asm/plpar_wrappers.h
@@ -334,6 +334,51 @@ static inline long plpar_get_cpu_characteristics(struct h_cpu_char_result *p)
 	return rc;
 }
 
+/*
+ * Wrapper to H_RPT_INVALIDATE hcall that handles return values appropriately
+ *
+ * - Returns H_SUCCESS on success
+ * - For H_BUSY return value, we retry the hcall.
+ * - For any other hcall failures, attempt a full flush once before
+ *   resorting to BUG().
+ *
+ * Note: This hcall is expected to fail only very rarely. The correct
+ * error recovery of killing the process/guest will be eventually
+ * needed.
+ */
+static inline long pseries_rpt_invalidate(u32 pid, u64 target, u64 type,
+					  u64 page_sizes, u64 start, u64 end)
+{
+	long rc;
+	unsigned long all;
+
+	while (true) {
+		rc = plpar_hcall_norets(H_RPT_INVALIDATE, pid, target, type,
+					page_sizes, start, end);
+		if (rc == H_BUSY) {
+			cpu_relax();
+			continue;
+		} else if (rc == H_SUCCESS)
+			return rc;
+
+		/* Flush request failed, try with a full flush once */
+		if (type & H_RPTI_TYPE_NESTED)
+			all = H_RPTI_TYPE_NESTED | H_RPTI_TYPE_NESTED_ALL;
+		else
+			all = H_RPTI_TYPE_ALL;
+retry:
+		rc = plpar_hcall_norets(H_RPT_INVALIDATE, pid, target,
+					all, page_sizes, 0, -1UL);
+		if (rc == H_BUSY) {
+			cpu_relax();
+			goto retry;
+		} else if (rc == H_SUCCESS)
+			return rc;
+
+		BUG();
+	}
+}
+
 #else /* !CONFIG_PPC_PSERIES */
 
 static inline long plpar_set_ciabr(unsigned long ciabr)
@@ -346,6 +391,13 @@ static inline long plpar_pte_read_4(unsigned long flags, unsigned long ptex,
 {
 	return 0;
 }
+
+static inline long pseries_rpt_invalidate(u32 pid, u64 target, u64 type,
+					  u64 page_sizes, u64 start, u64 end)
+{
+	return 0;
+}
+
 #endif /* CONFIG_PPC_PSERIES */
 
 #endif /* _ASM_POWERPC_PLPAR_WRAPPERS_H */