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Re: [PULL 1/2] tpm: CRB: Use ram_device for "tpm-crb-cmd" region
From: |
Igor Mammedov |
Subject: |
Re: [PULL 1/2] tpm: CRB: Use ram_device for "tpm-crb-cmd" region |
Date: |
Fri, 4 Feb 2022 13:08:46 +0100 |
On Thu, 03 Feb 2022 15:35:35 -0700
Alex Williamson <alex.williamson@redhat.com> wrote:
> From: Eric Auger <eric.auger@redhat.com>
>
> Representing the CRB cmd/response buffer as a standard
> RAM region causes some trouble when the device is used
> with VFIO. Indeed VFIO attempts to DMA_MAP this region
> as usual RAM but this latter does not have a valid page
> size alignment causing such an error report:
> "vfio_listener_region_add received unaligned region".
> To allow VFIO to detect that failing dma mapping
> this region is not an issue, let's use a ram_device
> memory region type instead.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Tested-by: Stefan Berger <stefanb@linux.ibm.com>
> Acked-by: Stefan Berger <stefanb@linux.ibm.com>
> [PMD: Keep tpm_crb.c in meson's softmmu_ss]
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Link: https://lore.kernel.org/r/20220120001242.230082-2-f4bug@amsat.org
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
> hw/tpm/tpm_crb.c | 22 ++++++++++++++++++++--
> 1 file changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/hw/tpm/tpm_crb.c b/hw/tpm/tpm_crb.c
> index 58ebd1469c35..be0884ea6031 100644
> --- a/hw/tpm/tpm_crb.c
> +++ b/hw/tpm/tpm_crb.c
> @@ -25,6 +25,7 @@
> #include "sysemu/tpm_backend.h"
> #include "sysemu/tpm_util.h"
> #include "sysemu/reset.h"
> +#include "exec/cpu-common.h"
> #include "tpm_prop.h"
> #include "tpm_ppi.h"
> #include "trace.h"
> @@ -43,6 +44,7 @@ struct CRBState {
>
> bool ppi_enabled;
> TPMPPI ppi;
> + uint8_t *crb_cmd_buf;
> };
> typedef struct CRBState CRBState;
>
> @@ -291,10 +293,14 @@ static void tpm_crb_realize(DeviceState *dev, Error
> **errp)
> return;
> }
>
> + s->crb_cmd_buf = qemu_memalign(qemu_real_host_page_size,
> + HOST_PAGE_ALIGN(CRB_CTRL_CMD_SIZE));
> +
> memory_region_init_io(&s->mmio, OBJECT(s), &tpm_crb_memory_ops, s,
> "tpm-crb-mmio", sizeof(s->regs));
> - memory_region_init_ram(&s->cmdmem, OBJECT(s),
> - "tpm-crb-cmd", CRB_CTRL_CMD_SIZE, errp);
> + memory_region_init_ram_device_ptr(&s->cmdmem, OBJECT(s), "tpm-crb-cmd",
> + CRB_CTRL_CMD_SIZE, s->crb_cmd_buf);
> + vmstate_register_ram(&s->cmdmem, DEVICE(s));
Does it need a compat knob for the case of migrating to older QEMU/machine type,
not to end-up with target aborting migration when it sees unknown section.
> memory_region_add_subregion(get_system_memory(),
> TPM_CRB_ADDR_BASE, &s->mmio);
> @@ -309,12 +315,24 @@ static void tpm_crb_realize(DeviceState *dev, Error
> **errp)
> qemu_register_reset(tpm_crb_reset, dev);
> }
>
> +static void tpm_crb_unrealize(DeviceState *dev)
> +{
> + CRBState *s = CRB(dev);
> +
likewise, should vmstate be unregistered here, before freeing
actually happens?
> + qemu_vfree(s->crb_cmd_buf);
> +
> + if (s->ppi_enabled) {
> + qemu_vfree(s->ppi.buf);
> + }
> +}
> +
> static void tpm_crb_class_init(ObjectClass *klass, void *data)
> {
> DeviceClass *dc = DEVICE_CLASS(klass);
> TPMIfClass *tc = TPM_IF_CLASS(klass);
>
> dc->realize = tpm_crb_realize;
> + dc->unrealize = tpm_crb_unrealize;
> device_class_set_props(dc, tpm_crb_properties);
> dc->vmsd = &vmstate_tpm_crb;
> dc->user_creatable = true;
>
>
>