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-rw-r--r--hw/ppc/spapr_hcall.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
index f69ce4f..436f5e2 100644
--- a/hw/ppc/spapr_hcall.c
+++ b/hw/ppc/spapr_hcall.c
@@ -1473,6 +1473,35 @@ static target_ulong h_client_architecture_support(PowerPCCPU *cpu,
guest_radix = spapr_ovec_test(ov5_guest, OV5_MMU_RADIX_300);
spapr_ovec_clear(ov5_guest, OV5_MMU_RADIX_300);
+ /*
+ * HPT resizing is a bit of a special case, because when enabled
+ * we assume an HPT guest will support it until it says it
+ * doesn't, instead of assuming it won't support it until it says
+ * it does. Strictly speaking that approach could break for
+ * guests which don't make a CAS call, but those are so old we
+ * don't care about them. Without that assumption we'd have to
+ * make at least a temporary allocation of an HPT sized for max
+ * memory, which could be impossibly difficult under KVM HV if
+ * maxram is large.
+ */
+ if (!guest_radix && !spapr_ovec_test(ov5_guest, OV5_HPT_RESIZE)) {
+ int maxshift = spapr_hpt_shift_for_ramsize(MACHINE(spapr)->maxram_size);
+
+ if (spapr->resize_hpt == SPAPR_RESIZE_HPT_REQUIRED) {
+ error_report(
+ "h_client_architecture_support: Guest doesn't support HPT resizing, but resize-hpt=required");
+ exit(1);
+ }
+
+ if (spapr->htab_shift < maxshift) {
+ /* Guest doesn't know about HPT resizing, so we
+ * pre-emptively resize for the maximum permitted RAM. At
+ * the point this is called, nothing should have been
+ * entered into the existing HPT */
+ spapr_reallocate_hpt(spapr, maxshift, &error_fatal);
+ }
+ }
+
/* NOTE: there are actually a number of ov5 bits where input from the
* guest is always zero, and the platform/QEMU enables them independently
* of guest input. To model these properly we'd want some sort of mask,