On Wed, Jun 21, 2023 at 7:34 AM Igor Mammedov <imamm...@redhat.com> wrote:
> On Tue, 20 Jun 2023 13:24:57 -0400
> Joel Upham <jupham...@gmail.com> wrote:
>
> > Resetting pci devices after s3 causes guest freezes, as xen usually
> > likes to handle resetting devices.
>
> I'd prefer Xen side being fixed instead of hacking reset logic in qemu/q35.
>
> Handling of ACPI and initialization of memory is done in hvmloader from my
understanding.
What I noticed was when qemu attempted to reset devices, they became
unusable or would freeze the guest. It is very possible
that I am missing something that piix is doing to correctly reset, so any
input I can get to make this better
is welcome.
>
> > Signed-off-by: Joel Upham <jupham...@gmail.com>
> > ---
> > hw/acpi/ich9.c | 12 ++++++++----
> > hw/pci-host/q35.c | 3 ++-
> > 2 files changed, 10 insertions(+), 5 deletions(-)
> >
> > diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
> > index 1c236be1c7..234706a191 100644
> > --- a/hw/acpi/ich9.c
> > +++ b/hw/acpi/ich9.c
> > @@ -143,7 +143,8 @@ static int ich9_pm_post_load(void *opaque, int
> version_id)
> > {
> > ICH9LPCPMRegs *pm = opaque;
> > uint32_t pm_io_base = pm->pm_io_base;
> > - pm->pm_io_base = 0;
> > + if (!xen_enabled())
> > + pm->pm_io_base = 0;
> > ich9_pm_iospace_update(pm, pm_io_base);
> > return 0;
> > }
> > @@ -274,7 +275,10 @@ static void pm_reset(void *opaque)
> > acpi_pm1_evt_reset(&pm->acpi_regs);
> > acpi_pm1_cnt_reset(&pm->acpi_regs);
> > acpi_pm_tmr_reset(&pm->acpi_regs);
> > - acpi_gpe_reset(&pm->acpi_regs);
> > + /* Noticed guest freezing in xen when this was reset after S3. */
> > + if (!xen_enabled()) {
> > + acpi_gpe_reset(&pm->acpi_regs);
> > + }
> >
> > pm->smi_en = 0;
> > if (!pm->smm_enabled) {
> > @@ -322,7 +326,7 @@ void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs
> *pm, qemu_irq sci_irq)
> > acpi_pm_tco_init(&pm->tco_regs, &pm->io);
> > }
> >
> > - if (pm->acpi_pci_hotplug.use_acpi_hotplug_bridge) {
> > + if (pm->acpi_pci_hotplug.use_acpi_hotplug_bridge || xen_enabled()) {
> > acpi_pcihp_init(OBJECT(lpc_pci),
> > &pm->acpi_pci_hotplug,
> > pci_get_bus(lpc_pci),
> > @@ -345,7 +349,7 @@ void ich9_pm_init(PCIDevice *lpc_pci, ICH9LPCPMRegs
> *pm, qemu_irq sci_irq)
> > legacy_acpi_cpu_hotplug_init(pci_address_space_io(lpc_pci),
> > OBJECT(lpc_pci), &pm->gpe_cpu, ICH9_CPU_HOTPLUG_IO_BASE);
> >
> > - if (pm->acpi_memory_hotplug.is_enabled) {
> > + if (pm->acpi_memory_hotplug.is_enabled || xen_enabled()) {
> > acpi_memory_hotplug_init(pci_address_space_io(lpc_pci),
> OBJECT(lpc_pci),
> > &pm->acpi_memory_hotplug,
> > ACPI_MEMORY_HOTPLUG_BASE);
> > diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
> > index 1fe4e5a5c9..5891839ce9 100644
> > --- a/hw/pci-host/q35.c
> > +++ b/hw/pci-host/q35.c
> > @@ -580,7 +580,8 @@ static void mch_reset(DeviceState *qdev)
> > d->config[MCH_HOST_BRIDGE_F_SMBASE] = 0;
> > d->wmask[MCH_HOST_BRIDGE_F_SMBASE] = 0xff;
> >
> > - mch_update(mch);
> > + if (!xen_enabled())
> > + mch_update(mch);
> > }
> >
> > static void mch_realize(PCIDevice *d, Error **errp)
>
>
