From 04f7fe2423a4de8d2fea7068b3fb316e15e76eaa Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Tue, 19 Jan 2021 15:09:49 -0500 Subject: [PATCH 1/9] spapr: Improve handling of fdt buffer size RH-Author: Greg Kurz Message-id: <20210119150954.1017058-2-gkurz@redhat.com> Patchwork-id: 100682 O-Subject: [RHEL-8.4.0 qemu-kvm PATCH v2 1/6] spapr: Improve handling of fdt buffer size Bugzilla: 1901837 RH-Acked-by: Miroslav Rezanina RH-Acked-by: Laurent Vivier RH-Acked-by: David Gibson From: David Gibson Previously, spapr_build_fdt() constructed the device tree in a fixed buffer of size FDT_MAX_SIZE. This is a bit inflexible, but more importantly it's awkward for the case where we use it during CAS. In that case the guest firmware supplies a buffer and we have to awkwardly check that what we generated fits into it afterwards, after doing a lot of size checks during spapr_build_fdt(). Simplify this by having spapr_build_fdt() take a 'space' parameter. For the CAS case, we pass in the buffer size provided by SLOF, for the machine init case, we continue to pass FDT_MAX_SIZE. Signed-off-by: David Gibson Reviewed-by: Cedric Le Goater Reviewed-by: Greg Kurz (cherry picked from commit 97b32a6afa78ae68fb16344b9a144b6f433f42a2) Signed-off-by: Greg Kurz Signed-off-by: Jon Maloy --- hw/ppc/spapr.c | 33 +++++++++++---------------------- 1 file changed, 11 insertions(+), 22 deletions(-) diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index c74079702d..92f63ad035 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -918,7 +918,8 @@ static bool spapr_hotplugged_dev_before_cas(void) return false; } -static void *spapr_build_fdt(SpaprMachineState *spapr, bool reset); +static void *spapr_build_fdt(SpaprMachineState *spapr, bool reset, + size_t space); int spapr_h_cas_compose_response(SpaprMachineState *spapr, target_ulong addr, target_ulong size, @@ -931,24 +932,17 @@ int spapr_h_cas_compose_response(SpaprMachineState *spapr, return 1; } - if (size < sizeof(hdr) || size > FW_MAX_SIZE) { - error_report("SLOF provided an unexpected CAS buffer size " - TARGET_FMT_lu " (min: %zu, max: %u)", - size, sizeof(hdr), FW_MAX_SIZE); + if (size < sizeof(hdr)) { + error_report("SLOF provided insufficient CAS buffer " + TARGET_FMT_lu " (min: %zu)", size, sizeof(hdr)); exit(EXIT_FAILURE); } size -= sizeof(hdr); - fdt = spapr_build_fdt(spapr, false); + fdt = spapr_build_fdt(spapr, false, size); _FDT((fdt_pack(fdt))); - if (fdt_totalsize(fdt) + sizeof(hdr) > size) { - g_free(fdt); - trace_spapr_cas_failed(size); - return -1; - } - cpu_physical_memory_write(addr, &hdr, sizeof(hdr)); cpu_physical_memory_write(addr + sizeof(hdr), fdt, fdt_totalsize(fdt)); trace_spapr_cas_continue(fdt_totalsize(fdt) + sizeof(hdr)); @@ -1198,7 +1192,8 @@ static void spapr_dt_hypervisor(SpaprMachineState *spapr, void *fdt) } } -static void *spapr_build_fdt(SpaprMachineState *spapr, bool reset) +static void *spapr_build_fdt(SpaprMachineState *spapr, bool reset, + size_t space) { MachineState *machine = MACHINE(spapr); MachineClass *mc = MACHINE_GET_CLASS(machine); @@ -1208,8 +1203,8 @@ static void *spapr_build_fdt(SpaprMachineState *spapr, bool reset) SpaprPhbState *phb; char *buf; - fdt = g_malloc0(FDT_MAX_SIZE); - _FDT((fdt_create_empty_tree(fdt, FDT_MAX_SIZE))); + fdt = g_malloc0(space); + _FDT((fdt_create_empty_tree(fdt, space))); /* Root node */ _FDT(fdt_setprop_string(fdt, 0, "device_type", "chrp")); @@ -1724,19 +1719,13 @@ static void spapr_machine_reset(MachineState *machine) */ fdt_addr = MIN(spapr->rma_size, RTAS_MAX_ADDR) - FDT_MAX_SIZE; - fdt = spapr_build_fdt(spapr, true); + fdt = spapr_build_fdt(spapr, true, FDT_MAX_SIZE); rc = fdt_pack(fdt); /* Should only fail if we've built a corrupted tree */ assert(rc == 0); - if (fdt_totalsize(fdt) > FDT_MAX_SIZE) { - error_report("FDT too big ! 0x%x bytes (max is 0x%x)", - fdt_totalsize(fdt), FDT_MAX_SIZE); - exit(1); - } - /* Load the fdt */ qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt)); cpu_physical_memory_write(fdt_addr, fdt, fdt_totalsize(fdt)); -- 2.18.2