Re: [QEMU][PATCH v4 09/10] hw/arm: introduce xenpvh machine

[Stefano Stabellini]

On Wed, 25 Jan 2023, Vikram Garhwal wrote:
> Add a new machine xenpvh which creates a IOREQ server to register/connect with
> Xen Hypervisor.
> 
> Optional: When CONFIG_TPM is enabled, it also creates a tpm-tis-device, adds a
> TPM emulator and connects to swtpm running on host machine via chardev socket
> and support TPM functionalities for a guest domain.
> 
> Extra command line for aarch64 xenpvh QEMU to connect to swtpm:
>     -chardev socket,id=chrtpm,path=/tmp/myvtpm2/swtpm-sock \
>     -tpmdev emulator,id=tpm0,chardev=chrtpm \
>     -machine tpm-base-addr=0x0c000000 \
> 
> swtpm implements a TPM software emulator(TPM 1.2 & TPM 2) built on libtpms and
> provides access to TPM functionality over socket, chardev and CUSE interface.
> Github repo: https://github.com/stefanberger/swtpm
> Example for starting swtpm on host machine:
>     mkdir /tmp/vtpm2
>     swtpm socket --tpmstate dir=/tmp/vtpm2 \
>     --ctrl type=unixio,path=/tmp/vtpm2/swtpm-sock &
> 
> Signed-off-by: Vikram Garhwal <vikram.garhwal@amd.com>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
> ---
>  docs/system/arm/xenpvh.rst    |  34 +++++++
>  docs/system/target-arm.rst    |   1 +
>  hw/arm/meson.build            |   2 +
>  hw/arm/xen_arm.c              | 184 ++++++++++++++++++++++++++++++++++
>  include/hw/arm/xen_arch_hvm.h |   9 ++
>  include/hw/xen/arch_hvm.h     |   2 +
>  6 files changed, 232 insertions(+)
>  create mode 100644 docs/system/arm/xenpvh.rst
>  create mode 100644 hw/arm/xen_arm.c
>  create mode 100644 include/hw/arm/xen_arch_hvm.h
> 
> diff --git a/docs/system/arm/xenpvh.rst b/docs/system/arm/xenpvh.rst
> new file mode 100644
> index 0000000000..e1655c7ab8
> --- /dev/null
> +++ b/docs/system/arm/xenpvh.rst
> @@ -0,0 +1,34 @@
> +XENPVH (``xenpvh``)
> +=========================================
> +This machine creates a IOREQ server to register/connect with Xen Hypervisor.
> +
> +When TPM is enabled, this machine also creates a tpm-tis-device at a user 
> input
> +tpm base address, adds a TPM emulator and connects to a swtpm application
> +running on host machine via chardev socket. This enables xenpvh to support 
> TPM
> +functionalities for a guest domain.
> +
> +More information about TPM use and installing swtpm linux application can be
> +found at: docs/specs/tpm.rst.
> +
> +Example for starting swtpm on host machine:
> +.. code-block:: console
> +
> +    mkdir /tmp/vtpm2
> +    swtpm socket --tpmstate dir=/tmp/vtpm2 \
> +    --ctrl type=unixio,path=/tmp/vtpm2/swtpm-sock &
> +
> +Sample QEMU xenpvh commands for running and connecting with Xen:
> +.. code-block:: console
> +
> +    qemu-system-aarch64 -xen-domid 1 \
> +    -chardev socket,id=libxl-cmd,path=qmp-libxl-1,server=on,wait=off \
> +    -mon chardev=libxl-cmd,mode=control \
> +    -chardev 
> socket,id=libxenstat-cmd,path=qmp-libxenstat-1,server=on,wait=off \
> +    -mon chardev=libxenstat-cmd,mode=control \
> +    -xen-attach -name guest0 -vnc none -display none -nographic \
> +    -machine xenpvh -m 1301 \
> +    -chardev socket,id=chrtpm,path=tmp/vtpm2/swtpm-sock \
> +    -tpmdev emulator,id=tpm0,chardev=chrtpm -machine tpm-base-addr=0x0C000000
> +
> +In above QEMU command, last two lines are for connecting xenpvh QEMU to swtpm
> +via chardev socket.
> diff --git a/docs/system/target-arm.rst b/docs/system/target-arm.rst
> index 91ebc26c6d..af8d7c77d6 100644
> --- a/docs/system/target-arm.rst
> +++ b/docs/system/target-arm.rst
> @@ -106,6 +106,7 @@ undocumented; you can get a complete list by running
>     arm/stm32
>     arm/virt
>     arm/xlnx-versal-virt
> +   arm/xenpvh
>  
>  Emulated CPU architecture support
>  =================================
> diff --git a/hw/arm/meson.build b/hw/arm/meson.build
> index b036045603..06bddbfbb8 100644
> --- a/hw/arm/meson.build
> +++ b/hw/arm/meson.build
> @@ -61,6 +61,8 @@ arm_ss.add(when: 'CONFIG_FSL_IMX7', if_true: 
> files('fsl-imx7.c', 'mcimx7d-sabre.
>  arm_ss.add(when: 'CONFIG_ARM_SMMUV3', if_true: files('smmuv3.c'))
>  arm_ss.add(when: 'CONFIG_FSL_IMX6UL', if_true: files('fsl-imx6ul.c', 
> 'mcimx6ul-evk.c'))
>  arm_ss.add(when: 'CONFIG_NRF51_SOC', if_true: files('nrf51_soc.c'))
> +arm_ss.add(when: 'CONFIG_XEN', if_true: files('xen_arm.c'))
> +arm_ss.add_all(xen_ss)
>  
>  softmmu_ss.add(when: 'CONFIG_ARM_SMMUV3', if_true: files('smmu-common.c'))
>  softmmu_ss.add(when: 'CONFIG_EXYNOS4', if_true: files('exynos4_boards.c'))
> diff --git a/hw/arm/xen_arm.c b/hw/arm/xen_arm.c
> new file mode 100644
> index 0000000000..12b19e3609
> --- /dev/null
> +++ b/hw/arm/xen_arm.c
> @@ -0,0 +1,184 @@
> +/*
> + * QEMU ARM Xen PV Machine
                   ^ PVH


> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a 
> copy
> + * of this software and associated documentation files (the "Software"), to 
> deal
> + * in the Software without restriction, including without limitation the 
> rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
> FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qemu/error-report.h"
> +#include "qapi/qapi-commands-migration.h"
> +#include "qapi/visitor.h"
> +#include "hw/boards.h"
> +#include "hw/sysbus.h"
> +#include "sysemu/block-backend.h"
> +#include "sysemu/tpm_backend.h"
> +#include "sysemu/sysemu.h"
> +#include "hw/xen/xen-legacy-backend.h"
> +#include "hw/xen/xen-hvm-common.h"
> +#include "sysemu/tpm.h"
> +#include "hw/xen/arch_hvm.h"
> +
> +#define TYPE_XEN_ARM  MACHINE_TYPE_NAME("xenpvh")
> +OBJECT_DECLARE_SIMPLE_TYPE(XenArmState, XEN_ARM)
> +
> +static MemoryListener xen_memory_listener = {
> +    .region_add = xen_region_add,
> +    .region_del = xen_region_del,
> +    .log_start = NULL,
> +    .log_stop = NULL,
> +    .log_sync = NULL,
> +    .log_global_start = NULL,
> +    .log_global_stop = NULL,
> +    .priority = 10,
> +};
> +
> +struct XenArmState {
> +    /*< private >*/
> +    MachineState parent;
> +
> +    XenIOState *state;
> +
> +    struct {
> +        uint64_t tpm_base_addr;
> +    } cfg;
> +};
> +
> +void arch_handle_ioreq(XenIOState *state, ioreq_t *req)
> +{
> +    hw_error("Invalid ioreq type 0x%x\n", req->type);
> +
> +    return;
> +}
> +
> +void arch_xen_set_memory(XenIOState *state, MemoryRegionSection *section,
> +                         bool add)
> +{
> +}
> +
> +void xen_hvm_modified_memory(ram_addr_t start, ram_addr_t length)
> +{
> +}
> +
> +void qmp_xen_set_global_dirty_log(bool enable, Error **errp)
> +{
> +}
> +
> +#ifdef CONFIG_TPM
> +static void xen_enable_tpm(XenArmState *xam)
> +{
> +    Error *errp = NULL;
> +    DeviceState *dev;
> +    SysBusDevice *busdev;
> +
> +    TPMBackend *be = qemu_find_tpm_be("tpm0");
> +    if (be == NULL) {
> +        DPRINTF("Couldn't fine the backend for tpm0\n");
> +        return;
> +    }
> +    dev = qdev_new(TYPE_TPM_TIS_SYSBUS);
> +    object_property_set_link(OBJECT(dev), "tpmdev", OBJECT(be), &errp);
> +    object_property_set_str(OBJECT(dev), "tpmdev", be->id, &errp);
> +    busdev = SYS_BUS_DEVICE(dev);
> +    sysbus_realize_and_unref(busdev, &error_fatal);
> +    sysbus_mmio_map(busdev, 0, xam->cfg.tpm_base_addr);
> +
> +    DPRINTF("Connected tpmdev at address 0x%lx\n", xam->cfg.tpm_base_addr);
> +}
> +#endif
> +
> +static void xen_arm_init(MachineState *machine)
> +{
> +    XenArmState *xam = XEN_ARM(machine);
> +
> +    xam->state =  g_new0(XenIOState, 1);
> +
> +    xen_register_ioreq(xam->state, machine->smp.cpus, xen_memory_listener);
> +
> +#ifdef CONFIG_TPM
> +    if (xam->cfg.tpm_base_addr) {
> +        xen_enable_tpm(xam);
> +    } else {
> +        DPRINTF("tpm-base-addr is not provided. TPM will not be enabled\n");
> +    }

I would remove the "else", we already have a DPRINTF at the end of
xen_enable_tpm.


> +#endif
> +
> +    return;

the return is unnecessary


> +}
> +
> +#ifdef CONFIG_TPM
> +static void xen_arm_get_tpm_base_addr(Object *obj, Visitor *v,
> +                                      const char *name, void *opaque,
> +                                      Error **errp)
> +{
> +    XenArmState *xam = XEN_ARM(obj);
> +    uint64_t value = xam->cfg.tpm_base_addr;
> +
> +    visit_type_uint64(v, name, &value, errp);
> +}
> +
> +static void xen_arm_set_tpm_base_addr(Object *obj, Visitor *v,
> +                                      const char *name, void *opaque,
> +                                      Error **errp)
> +{
> +    XenArmState *xam = XEN_ARM(obj);
> +    uint64_t value;
> +
> +    if (!visit_type_uint64(v, name, &value, errp)) {
> +        return;
> +    }
> +
> +    xam->cfg.tpm_base_addr = value;
> +}
> +#endif
> +
> +static void xen_arm_machine_class_init(ObjectClass *oc, void *data)
> +{
> +
> +    MachineClass *mc = MACHINE_CLASS(oc);
> +    mc->desc = "Xen Para-virtualized PC";
> +    mc->init = xen_arm_init;
> +    mc->max_cpus = 1;
> +    mc->default_machine_opts = "accel=xen";
> +
> +#ifdef CONFIG_TPM
> +    object_class_property_add(oc, "tpm-base-addr", "uint64_t",
> +                              xen_arm_get_tpm_base_addr,
> +                              xen_arm_set_tpm_base_addr,
> +                              NULL, NULL);
> +    object_class_property_set_description(oc, "tpm-base-addr",
> +                                          "Set Base address for TPM 
> device.");
> +
> +    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_TPM_TIS_SYSBUS);
> +#endif
> +}
> +
> +static const TypeInfo xen_arm_machine_type = {
> +    .name = TYPE_XEN_ARM,
> +    .parent = TYPE_MACHINE,
> +    .class_init = xen_arm_machine_class_init,
> +    .instance_size = sizeof(XenArmState),
> +};
> +
> +static void xen_arm_machine_register_types(void)
> +{
> +    type_register_static(&xen_arm_machine_type);
> +}
> +
> +type_init(xen_arm_machine_register_types)
> diff --git a/include/hw/arm/xen_arch_hvm.h b/include/hw/arm/xen_arch_hvm.h
> new file mode 100644
> index 0000000000..8fd645e723
> --- /dev/null
> +++ b/include/hw/arm/xen_arch_hvm.h
> @@ -0,0 +1,9 @@
> +#ifndef HW_XEN_ARCH_ARM_HVM_H
> +#define HW_XEN_ARCH_ARM_HVM_H
> +
> +#include <xen/hvm/ioreq.h>
> +void arch_handle_ioreq(XenIOState *state, ioreq_t *req);
> +void arch_xen_set_memory(XenIOState *state,
> +                         MemoryRegionSection *section,
> +                         bool add);
> +#endif
> diff --git a/include/hw/xen/arch_hvm.h b/include/hw/xen/arch_hvm.h
> index 26674648d8..c7c515220d 100644
> --- a/include/hw/xen/arch_hvm.h
> +++ b/include/hw/xen/arch_hvm.h
> @@ -1,3 +1,5 @@
>  #if defined(TARGET_I386) || defined(TARGET_X86_64)
>  #include "hw/i386/xen_arch_hvm.h"
> +#elif defined(TARGET_ARM) || defined(TARGET_ARM_64)
> +#include "hw/arm/xen_arch_hvm.h"
>  #endif
> -- 
> 2.17.0
>