On Wed, Aug 30, 2023 at 04:14:21PM +0000, Alexander Graf wrote: > The VMApple machine exposes AUX and ROOT block devices (as well as USB OTG > emulation) via virtio-pci as well as a special, simple backdoor platform > device. > > This patch implements this backdoor platform device to the best of my > understanding. I left out any USB OTG parts; they're only needed for > guest recovery and I don't understand the protocol yet.
Out of curiosity: This interface has no way to check the size of the block device? I guess that's not necessary in a boot loader that just parses a boot record and then loads the next stage... I posted comments below. Otherwise: Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com> > > Signed-off-by: Alexander Graf <g...@amazon.com> > > --- > > v1 -> v2: > > - Adapt to system_ss meson.build target > --- > include/hw/vmapple/bdif.h | 31 +++++ > hw/vmapple/bdif.c | 245 ++++++++++++++++++++++++++++++++++++++ > hw/vmapple/Kconfig | 2 + > hw/vmapple/meson.build | 1 + > hw/vmapple/trace-events | 5 + > 5 files changed, 284 insertions(+) > create mode 100644 include/hw/vmapple/bdif.h > create mode 100644 hw/vmapple/bdif.c > > diff --git a/include/hw/vmapple/bdif.h b/include/hw/vmapple/bdif.h > new file mode 100644 > index 0000000000..65ee43457b > --- /dev/null > +++ b/include/hw/vmapple/bdif.h > @@ -0,0 +1,31 @@ > +/* > + * VMApple Backdoor Interface > + * > + * Copyright © 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved. > + * > + * This work is licensed under the terms of the GNU GPL, version 2 or later. > + * See the COPYING file in the top-level directory. > + */ > + > +#ifndef HW_VMAPPLE_BDIF_H > +#define HW_VMAPPLE_BDIF_H > + > +#include "hw/sysbus.h" > +#include "qom/object.h" > + > +#define TYPE_VMAPPLE_BDIF "vmapple-bdif" > +OBJECT_DECLARE_SIMPLE_TYPE(VMAppleBdifState, VMAPPLE_BDIF) > + > +struct VMAppleBdifState { > + /* <private> */ > + SysBusDevice parent_obj; > + > + /* <public> */ > + BlockBackend *aux; > + BlockBackend *root; > + MemoryRegion mmio; > +}; > + > +#define VMAPPLE_BDIF_SIZE 0x00200000 > + > +#endif /* HW_VMAPPLE_BDIF_H */ > diff --git a/hw/vmapple/bdif.c b/hw/vmapple/bdif.c > new file mode 100644 > index 0000000000..36b5915ff3 > --- /dev/null > +++ b/hw/vmapple/bdif.c > @@ -0,0 +1,245 @@ > +/* > + * VMApple Backdoor Interface > + * > + * Copyright © 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved. > + * > + * This work is licensed under the terms of the GNU GPL, version 2 or later. > + * See the COPYING file in the top-level directory. > + */ > + > +#include "qemu/osdep.h" > +#include "hw/vmapple/bdif.h" > +#include "qemu/log.h" > +#include "qemu/module.h" > +#include "qapi/error.h" > +#include "trace.h" > +#include "hw/block/block.h" > +#include "sysemu/block-backend.h" > + > +#define REG_DEVID_MASK 0xffff0000 > +#define DEVID_ROOT 0x00000000 > +#define DEVID_AUX 0x00010000 > +#define DEVID_USB 0x00100000 > + > +#define REG_STATUS 0x0 > +#define REG_STATUS_ACTIVE BIT(0) > +#define REG_CFG 0x4 > +#define REG_CFG_ACTIVE BIT(1) > +#define REG_UNK1 0x8 > +#define REG_BUSY 0x10 > +#define REG_BUSY_READY BIT(0) > +#define REG_UNK2 0x400 > +#define REG_CMD 0x408 > +#define REG_NEXT_DEVICE 0x420 > +#define REG_UNK3 0x434 > + > +typedef struct vblk_sector { > + uint32_t pad; > + uint32_t pad2; > + uint32_t sector; > + uint32_t pad3; > +} VblkSector; > + > +typedef struct vblk_req_cmd { > + uint64_t addr; > + uint32_t len; > + uint32_t flags; > +} VblkReqCmd; > + > +typedef struct vblk_req { > + VblkReqCmd sector; > + VblkReqCmd data; > + VblkReqCmd retval; > +} VblkReq; > + > +#define VBLK_DATA_FLAGS_READ 0x00030001 > +#define VBLK_DATA_FLAGS_WRITE 0x00010001 > + > +#define VBLK_RET_SUCCESS 0 > +#define VBLK_RET_FAILED 1 > + > +static uint64_t bdif_read(void *opaque, hwaddr offset, unsigned size) > +{ > + uint64_t ret = -1; > + uint64_t devid = (offset & REG_DEVID_MASK); > + > + switch (offset & ~REG_DEVID_MASK) { > + case REG_STATUS: > + ret = REG_STATUS_ACTIVE; > + break; > + case REG_CFG: > + ret = REG_CFG_ACTIVE; > + break; > + case REG_UNK1: > + ret = 0x420; > + break; > + case REG_BUSY: > + ret = REG_BUSY_READY; > + break; > + case REG_UNK2: > + ret = 0x1; > + break; > + case REG_UNK3: > + ret = 0x0; > + break; > + case REG_NEXT_DEVICE: > + switch (devid) { > + case DEVID_ROOT: > + ret = 0x8000000; > + break; > + case DEVID_AUX: > + ret = 0x10000; > + break; > + } > + break; > + } > + > + trace_bdif_read(offset, size, ret); > + return ret; > +} > + > +static void le2cpu_sector(VblkSector *sector) > +{ > + sector->sector = le32_to_cpu(sector->sector); > +} > + > +static void le2cpu_reqcmd(VblkReqCmd *cmd) > +{ > + cmd->addr = le64_to_cpu(cmd->addr); > + cmd->len = le32_to_cpu(cmd->len); > + cmd->flags = le32_to_cpu(cmd->flags); > +} > + > +static void le2cpu_req(VblkReq *req) > +{ > + le2cpu_reqcmd(&req->sector); > + le2cpu_reqcmd(&req->data); > + le2cpu_reqcmd(&req->retval); > +} > + > +static void vblk_cmd(uint64_t devid, BlockBackend *blk, uint64_t value, > + uint64_t static_off) > +{ > + VblkReq req; > + VblkSector sector; > + uint64_t off = 0; > + char *buf = NULL; > + uint8_t ret = VBLK_RET_FAILED; > + int r; > + > + cpu_physical_memory_read(value, &req, sizeof(req)); Please zero req first so that when value is bogus and cpu_physical_memory_read() does not store to &req, we don't process req's uninitialized stack memory: VblkReq req = {}; > + le2cpu_req(&req); > + > + if (req.sector.len != sizeof(sector)) { > + ret = VBLK_RET_FAILED; > + goto out; > + } > + > + /* Read the vblk command */ > + cpu_physical_memory_read(req.sector.addr, §or, sizeof(sector)); Same here: VblkSectors sector = {}; > + le2cpu_sector(§or); > + > + off = sector.sector * 512ULL + static_off; > + > + /* Sanity check that we're not allocating bogus sizes */ > + if (req.data.len > (128 * 1024 * 1024)) { > + goto out; > + } > + > + buf = g_malloc0(req.data.len); > + switch (req.data.flags) { > + case VBLK_DATA_FLAGS_READ: > + r = blk_pread(blk, off, req.data.len, buf, 0); > + trace_bdif_vblk_read(devid == DEVID_AUX ? "aux" : "root", > + req.data.addr, off, req.data.len, r); > + if (r < 0) { > + goto out; > + } > + cpu_physical_memory_write(req.data.addr, buf, req.data.len); > + ret = VBLK_RET_SUCCESS; > + break; > + case VBLK_DATA_FLAGS_WRITE: > + /* Not needed, iBoot only reads */ > + break; > + default: > + break; > + } > + > +out: > + g_free(buf); > + cpu_physical_memory_write(req.retval.addr, &ret, 1); > +} > + > +static void bdif_write(void *opaque, hwaddr offset, > + uint64_t value, unsigned size) > +{ > + VMAppleBdifState *s = opaque; > + uint64_t devid = (offset & REG_DEVID_MASK); > + > + trace_bdif_write(offset, size, value); > + > + switch (offset & ~REG_DEVID_MASK) { > + case REG_CMD: > + switch (devid) { > + case DEVID_ROOT: > + vblk_cmd(devid, s->root, value, 0x0); > + break; > + case DEVID_AUX: > + vblk_cmd(devid, s->aux, value, 0x0); > + break; > + } > + break; > + } > +} > + > +static const MemoryRegionOps bdif_ops = { > + .read = bdif_read, > + .write = bdif_write, > + .endianness = DEVICE_NATIVE_ENDIAN, > + .valid = { > + .min_access_size = 1, > + .max_access_size = 8, > + }, > + .impl = { > + .min_access_size = 1, > + .max_access_size = 8, > + }, > +}; > + > +static void bdif_init(Object *obj) > +{ > + VMAppleBdifState *s = VMAPPLE_BDIF(obj); > + > + memory_region_init_io(&s->mmio, obj, &bdif_ops, obj, > + "VMApple Backdoor Interface", VMAPPLE_BDIF_SIZE); > + sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio); > +} > + > +static Property bdif_properties[] = { > + DEFINE_PROP_DRIVE("aux", VMAppleBdifState, aux), > + DEFINE_PROP_DRIVE("root", VMAppleBdifState, root), > + DEFINE_PROP_END_OF_LIST(), > +}; > + > +static void bdif_class_init(ObjectClass *klass, void *data) > +{ > + DeviceClass *dc = DEVICE_CLASS(klass); > + > + dc->desc = "VMApple Backdoor Interface"; > + device_class_set_props(dc, bdif_properties); > +} > + > +static const TypeInfo bdif_info = { > + .name = TYPE_VMAPPLE_BDIF, > + .parent = TYPE_SYS_BUS_DEVICE, > + .instance_size = sizeof(VMAppleBdifState), > + .instance_init = bdif_init, > + .class_init = bdif_class_init, > +}; > + > +static void bdif_register_types(void) > +{ > + type_register_static(&bdif_info); > +} > + > +type_init(bdif_register_types) > diff --git a/hw/vmapple/Kconfig b/hw/vmapple/Kconfig > index a73504d599..388a2bc60c 100644 > --- a/hw/vmapple/Kconfig > +++ b/hw/vmapple/Kconfig > @@ -1,3 +1,5 @@ > config VMAPPLE_AES > bool > > +config VMAPPLE_BDIF > + bool > diff --git a/hw/vmapple/meson.build b/hw/vmapple/meson.build > index bcd4dcb28d..d4624713de 100644 > --- a/hw/vmapple/meson.build > +++ b/hw/vmapple/meson.build > @@ -1 +1,2 @@ > system_ss.add(when: 'CONFIG_VMAPPLE_AES', if_true: files('aes.c')) > +system_ss.add(when: 'CONFIG_VMAPPLE_BDIF', if_true: files('bdif.c')) > diff --git a/hw/vmapple/trace-events b/hw/vmapple/trace-events > index 03585cdf0f..45c69de2e0 100644 > --- a/hw/vmapple/trace-events > +++ b/hw/vmapple/trace-events > @@ -18,3 +18,8 @@ aes_2_read(uint64_t offset, uint64_t res) > "offset=0x%"PRIx64" res=0x%"PRIx64 > aes_2_write_unknown(uint64_t offset) "offset=0x%"PRIx64 > aes_2_write(uint64_t offset, uint64_t val) "offset=0x%"PRIx64" val=0x%"PRIx64 > aes_dump_data(const char *desc, const char *hex) "%s%s" > + > +# bdif.c > +bdif_read(uint64_t offset, uint32_t size, uint64_t value) > "offset=0x%"PRIx64" size=0x%x value=0x%"PRIx64 > +bdif_write(uint64_t offset, uint32_t size, uint64_t value) > "offset=0x%"PRIx64" size=0x%x value=0x%"PRIx64 > +bdif_vblk_read(const char *dev, uint64_t addr, uint64_t offset, uint32_t > len, int r) "dev=%s addr=0x%"PRIx64" off=0x%"PRIx64" size=0x%x r=%d" > -- > 2.39.2 (Apple Git-143) > > > > > Amazon Development Center Germany GmbH > Krausenstr. 38 > 10117 Berlin > Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss > Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B > Sitz: Berlin > Ust-ID: DE 289 237 879 > >
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