From 28f5a716212b891eef3eadc2c5053c0e0c512e1d Mon Sep 17 00:00:00 2001 From: Daniel Henrique Barboza Date: Tue, 25 Aug 2020 18:57:49 -0300 Subject: ppc/spapr_nvdimm: do not enable support with 'nvdimm=off' The NVDIMM support for pSeries was introduced in 5.1, but it didn't contemplate the 'nvdimm' machine option that other archs uses. For every other arch, if no '-machine nvdimm(=on)' is present, it is assumed that the NVDIMM support is disabled. The user must explictly inform that the machine supports NVDIMM. For pseries-5.1 the 'nvdimm' option is completely ignored, and support is always assumed to exist. This leads to situations where the user is able to set 'nvdimm=off' but the guest boots up with the NVDIMMs anyway. Fixing this now, after 5.1 launch, can put the overall NVDIMM support for pseries in a strange place regarding this 'nvdimm' machine option. If we force everything to be like other archs, existing pseries-5.1 guests that didn't use 'nvdimm' to use NVDIMM devices will break. If we attempt to make the newer pseries machines (5.2+) behave like everyone else, but keep pseries-5.1 untouched, we'll have consistency problems on machine upgrade (5.1 will have different default values for NVDIMM support than 5.2). The common ground here is, if the user sets 'nvdimm=off', we must comply regardless of being 5.1 or 5.2+. This patch changes spapr_nvdimm_validate() to verify if the user set NVDIMM support off in the machine options and, in that case, error out if we have a NVDIMM device. The default value for 5.2+ pseries machines will still be 'nvdimm=on' when there is no 'nvdimm' option declared, just like it is today with pseries-5.1. In the end we'll have different default semantics from everyone else in the absence of the 'nvdimm' machine option, but this boat has sailed. Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1848887 Signed-off-by: Daniel Henrique Barboza Message-Id: <20200825215749.213536-4-danielhb413@gmail.com> Signed-off-by: David Gibson --- hw/ppc/spapr_nvdimm.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'hw/ppc/spapr_nvdimm.c') diff --git a/hw/ppc/spapr_nvdimm.c b/hw/ppc/spapr_nvdimm.c index bc2b654..95cbc30 100644 --- a/hw/ppc/spapr_nvdimm.c +++ b/hw/ppc/spapr_nvdimm.c @@ -27,13 +27,17 @@ #include "hw/ppc/spapr_nvdimm.h" #include "hw/mem/nvdimm.h" #include "qemu/nvdimm-utils.h" +#include "qemu/option.h" #include "hw/ppc/fdt.h" #include "qemu/range.h" +#include "sysemu/sysemu.h" void spapr_nvdimm_validate(HotplugHandler *hotplug_dev, NVDIMMDevice *nvdimm, uint64_t size, Error **errp) { const MachineClass *mc = MACHINE_GET_CLASS(hotplug_dev); + const MachineState *ms = MACHINE(hotplug_dev); + const char *nvdimm_opt = qemu_opt_get(qemu_get_machine_opts(), "nvdimm"); g_autofree char *uuidstr = NULL; QemuUUID uuid; int ret; @@ -43,6 +47,20 @@ void spapr_nvdimm_validate(HotplugHandler *hotplug_dev, NVDIMMDevice *nvdimm, return; } + /* + * NVDIMM support went live in 5.1 without considering that, in + * other archs, the user needs to enable NVDIMM support with the + * 'nvdimm' machine option and the default behavior is NVDIMM + * support disabled. It is too late to roll back to the standard + * behavior without breaking 5.1 guests. What we can do is to + * ensure that, if the user sets nvdimm=off, we error out + * regardless of being 5.1 or newer. + */ + if (!ms->nvdimms_state->is_enabled && nvdimm_opt) { + error_setg(errp, "nvdimm device found but 'nvdimm=off' was set"); + return; + } + if (object_property_get_int(OBJECT(nvdimm), NVDIMM_LABEL_SIZE_PROP, &error_abort) == 0) { error_setg(errp, "PAPR requires NVDIMM devices to have label-size set"); -- cgit v1.1