On Thu, Mar 12, 2020 at 09:27:32AM +0000, Shameerali Kolothum Thodi wrote: > > > > -----Original Message----- > > From: Michael S. Tsirkin [mailto:m...@redhat.com] > > Sent: 11 March 2020 21:10 > > To: Shameerali Kolothum Thodi <shameerali.kolothum.th...@huawei.com> > > Cc: qemu-devel@nongnu.org; qemu-...@nongnu.org; > > eric.au...@redhat.com; imamm...@redhat.com; peter.mayd...@linaro.org; > > shannon.zha...@gmail.com; xiaoguangrong.e...@gmail.com; > > da...@redhat.com; xuwei (O) <xuw...@huawei.com>; ler...@redhat.com; > > Linuxarm <linux...@huawei.com> > > Subject: Re: [PATCH v3 02/10] fw_cfg: Migrate ACPI table mr sizes separately > > > > On Wed, Mar 11, 2020 at 05:20:06PM +0000, Shameer Kolothum wrote: > > > Any sub-page size update to ACPI table MRs will be lost during > > > migration, as we use aligned size in ram_load_precopy() -> > > > qemu_ram_resize() path. This will result in inconsistency in sizes > > > between source and destination. In order to avoid this, save and > > > restore them separately during migration. > > > > Is there a reason this is part of nvdimm patchset? > > Not really. But this problem is more visible if we have nvdimm hotplug > support added to arm/virt. On x86, both acpi table and linker MRs are already > aligned and I don't know a use case where you can change RSDP MR size(See > below). > > > > > Hmm but for old machine types we still have a problem right? > > How about aligning size on source for them? > > Then there won't be an inconsistency across migration. > > Wastes some boot time/memory but maybe that's better > > than a chance of not booting ... > > Right. That was considered. On x86, except RSDP MR, both the LINKER and ACPI > TABLE MRs are already aligned/padded. And we cannot make RSDP mr aligned > as it will break the seabios based boot.
Hmm. So right now if we migrate just before RSDP is read, there's a failure? > So a generic solution based on alignment > is not possible unless we guarantee that RSDP is not going to be modified. > > What we could do for Arm/virt is just follow the x86 way and add padding for > table and linker MRs. But this was discussed before and IIRC, was not well > received. > > Thanks, > Shameer > > > > Suggested-by: David Hildenbrand <da...@redhat.com> > > > Signed-off-by: Shameer Kolothum <shameerali.kolothum.th...@huawei.com> > > > --- > > > Please find the discussion here, > > > https://patchwork.kernel.org/patch/11339591/ > > > --- > > > hw/core/machine.c | 1 + > > > hw/nvram/fw_cfg.c | 86 > > ++++++++++++++++++++++++++++++++++++++- > > > include/hw/nvram/fw_cfg.h | 6 +++ > > > 3 files changed, 92 insertions(+), 1 deletion(-) > > > > > > diff --git a/hw/core/machine.c b/hw/core/machine.c > > > index 9e8c06036f..6d960bd47f 100644 > > > --- a/hw/core/machine.c > > > +++ b/hw/core/machine.c > > > @@ -39,6 +39,7 @@ GlobalProperty hw_compat_4_2[] = { > > > { "usb-redir", "suppress-remote-wake", "off" }, > > > { "qxl", "revision", "4" }, > > > { "qxl-vga", "revision", "4" }, > > > + { "fw_cfg", "acpi-mr-restore", "false" }, > > > }; > > > const size_t hw_compat_4_2_len = G_N_ELEMENTS(hw_compat_4_2); > > > > > > diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c > > > index 179b302f01..36d1e32f83 100644 > > > --- a/hw/nvram/fw_cfg.c > > > +++ b/hw/nvram/fw_cfg.c > > > @@ -39,6 +39,7 @@ > > > #include "qemu/config-file.h" > > > #include "qemu/cutils.h" > > > #include "qapi/error.h" > > > +#include "hw/acpi/aml-build.h" > > > > > > #define FW_CFG_FILE_SLOTS_DFLT 0x20 > > > > > > @@ -610,6 +611,50 @@ bool fw_cfg_dma_enabled(void *opaque) > > > return s->dma_enabled; > > > } > > > > > > +static bool fw_cfg_acpi_mr_restore(void *opaque) > > > +{ > > > + FWCfgState *s = opaque; > > > + return s->acpi_mr_restore; > > > +} > > > + > > > +static void fw_cfg_update_mr(FWCfgState *s, uint16_t key, size_t size) > > > +{ > > > + MemoryRegion *mr; > > > + ram_addr_t offset; > > > + int arch = !!(key & FW_CFG_ARCH_LOCAL); > > > + void *ptr; > > > + > > > + key &= FW_CFG_ENTRY_MASK; > > > + assert(key < fw_cfg_max_entry(s)); > > > + > > > + ptr = s->entries[arch][key].data; > > > + mr = memory_region_from_host(ptr, &offset); > > > + > > > + memory_region_ram_resize(mr, size, &error_abort); > > > +} > > > + > > > +static int fw_cfg_acpi_mr_restore_post_load(void *opaque, int version_id) > > > +{ > > > + FWCfgState *s = opaque; > > > + int i, index; > > > + > > > + assert(s->files); > > > + > > > + index = be32_to_cpu(s->files->count); > > > + > > > + for (i = 0; i < index; i++) { > > > + if (!strcmp(s->files->f[i].name, ACPI_BUILD_TABLE_FILE)) { > > > + fw_cfg_update_mr(s, FW_CFG_FILE_FIRST + i, > > s->table_mr_size); > > > + } else if (!strcmp(s->files->f[i].name, ACPI_BUILD_LOADER_FILE)) > > > { > > > + fw_cfg_update_mr(s, FW_CFG_FILE_FIRST + i, > > s->linker_mr_size); > > > + } else if (!strcmp(s->files->f[i].name, ACPI_BUILD_RSDP_FILE)) { > > > + fw_cfg_update_mr(s, FW_CFG_FILE_FIRST + i, > > s->rsdp_mr_size); > > > + } > > > + } > > > + > > > + return 0; > > > +} > > > + > > > static const VMStateDescription vmstate_fw_cfg_dma = { > > > .name = "fw_cfg/dma", > > > .needed = fw_cfg_dma_enabled, > > > @@ -619,6 +664,20 @@ static const VMStateDescription > > vmstate_fw_cfg_dma = { > > > }, > > > }; > > > > > > +static const VMStateDescription vmstate_fw_cfg_acpi_mr = { > > > + .name = "fw_cfg/acpi_mr", > > > + .version_id = 1, > > > + .minimum_version_id = 1, > > > + .needed = fw_cfg_acpi_mr_restore, > > > + .post_load = fw_cfg_acpi_mr_restore_post_load, > > > + .fields = (VMStateField[]) { > > > + VMSTATE_UINT64(table_mr_size, FWCfgState), > > > + VMSTATE_UINT64(linker_mr_size, FWCfgState), > > > + VMSTATE_UINT64(rsdp_mr_size, FWCfgState), > > > + VMSTATE_END_OF_LIST() > > > + }, > > > +}; > > > + > > > static const VMStateDescription vmstate_fw_cfg = { > > > .name = "fw_cfg", > > > .version_id = 2, > > > @@ -631,6 +690,7 @@ static const VMStateDescription vmstate_fw_cfg = { > > > }, > > > .subsections = (const VMStateDescription*[]) { > > > &vmstate_fw_cfg_dma, > > > + &vmstate_fw_cfg_acpi_mr, > > > NULL, > > > } > > > }; > > > @@ -815,6 +875,23 @@ static struct { > > > #define FW_CFG_ORDER_OVERRIDE_LAST 200 > > > }; > > > > > > +/* > > > + * Any sub-page size update to these table MRs will be lost during > > > migration, > > > + * as we use aligned size in ram_load_precopy() -> qemu_ram_resize() > > > path. > > > + * In order to avoid the inconsistency in sizes save them seperately and > > > + * migrate over in vmstate post_load(). > > > + */ > > > +static void fw_cfg_acpi_mr_save(FWCfgState *s, const char *filename, > > size_t len) > > > +{ > > > + if (!strcmp(filename, ACPI_BUILD_TABLE_FILE)) { > > > + s->table_mr_size = len; > > > + } else if (!strcmp(filename, ACPI_BUILD_LOADER_FILE)) { > > > + s->linker_mr_size = len; > > > + } else if (!strcmp(filename, ACPI_BUILD_RSDP_FILE)) { > > > + s->rsdp_mr_size = len; > > > + } > > > +} > > > + > > > static int get_fw_cfg_order(FWCfgState *s, const char *name) > > > { > > > int i; > > > @@ -914,6 +991,7 @@ void fw_cfg_add_file_callback(FWCfgState *s, > > const char *filename, > > > trace_fw_cfg_add_file(s, index, s->files->f[index].name, len); > > > > > > s->files->count = cpu_to_be32(count+1); > > > + fw_cfg_acpi_mr_save(s, filename, len); > > > } > > > > > > void fw_cfg_add_file(FWCfgState *s, const char *filename, > > > @@ -937,6 +1015,7 @@ void *fw_cfg_modify_file(FWCfgState *s, const char > > *filename, > > > ptr = fw_cfg_modify_bytes_read(s, FW_CFG_FILE_FIRST + i, > > > data, len); > > > s->files->f[i].size = cpu_to_be32(len); > > > + fw_cfg_acpi_mr_save(s, filename, len); > > > return ptr; > > > } > > > } > > > @@ -973,7 +1052,10 @@ static void fw_cfg_machine_ready(struct Notifier > > *n, void *data) > > > qemu_register_reset(fw_cfg_machine_reset, s); > > > } > > > > > > - > > > +static Property fw_cfg_properties[] = { > > > + DEFINE_PROP_BOOL("acpi-mr-restore", FWCfgState, acpi_mr_restore, > > true), > > > + DEFINE_PROP_END_OF_LIST(), > > > +}; > > > > > > static void fw_cfg_common_realize(DeviceState *dev, Error **errp) > > > { > > > @@ -1097,6 +1179,8 @@ static void fw_cfg_class_init(ObjectClass *klass, > > void *data) > > > > > > dc->reset = fw_cfg_reset; > > > dc->vmsd = &vmstate_fw_cfg; > > > + > > > + device_class_set_props(dc, fw_cfg_properties); > > > } > > > > > > static const TypeInfo fw_cfg_info = { > > > diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h > > > index b5291eefad..457fee7425 100644 > > > --- a/include/hw/nvram/fw_cfg.h > > > +++ b/include/hw/nvram/fw_cfg.h > > > @@ -53,6 +53,12 @@ struct FWCfgState { > > > dma_addr_t dma_addr; > > > AddressSpace *dma_as; > > > MemoryRegion dma_iomem; > > > + > > > + /* restore during migration */ > > > + bool acpi_mr_restore; > > > + size_t table_mr_size; > > > + size_t linker_mr_size; > > > + size_t rsdp_mr_size; > > > }; > > > > > > struct FWCfgIoState { > > > -- > > > 2.17.1 > > >
