On Wed, 28 May 2014 18:38:13 +0200
Vasilis Liaskovitis <vasilis.liaskovi...@profitbricks.com> wrote:
> On Wed, May 28, 2014 at 03:26:42PM +0200, Igor Mammedov wrote:
> > On Wed, 28 May 2014 14:23:13 +0200
> > Vasilis Liaskovitis <vasilis.liaskovi...@profitbricks.com> wrote:
> >
> > > On Wed, May 28, 2014 at 10:07:22AM +0200, Igor Mammedov wrote:
> > > > On Tue, 27 May 2014 17:57:31 +0200
> > > > Anshul Makkar <anshul.mak...@profitbricks.com> wrote:
> > > >
> > > > > Hi,
> > > > >
> > > > > I tested the hot unplug patch and doesn't seem to work properly with
> > > > > Debian
> > > > > 6 and Ubuntu host.
> > > > >
> > > > > Scenario:
> > > > > I added 3 dimm devices of 1G each:
> > > > >
> > > > > object_add memory-ram,id=ram0,size=1G, device_add
> > > > > dimm,id=dimm1,memdev=ram0
> > > > >
> > > > > object_add memory-ram,id=ram1,size=1G, device_add
> > > > > dimm,id=dimm2,memdev=ram1
> > > > >
> > > > > object_add memory-ram,id=ram2,size=1G, device_add
> > > > > dimm,id=dimm3,memdev=ram2
> > > > >
> > > > > device_del dimm3: I get the OST EVENT EJECT 0x3 and OST STATUS as
> > > > > 0x84(IN
> > > > > PROGRESS) If I check on the guest, the device has been successfully
> > > > > removed. But no OST EJECT SUCCESS event was received.
> > > > I think there should be a SUCCESS event,
> > > > it should be investigated from the guest side first, OST support in
> > > > kernel
> > > > is relatively new.
> > >
> > > When testing older guest kernel (3.11), _OST success events are not sent
> > > from the guest. I haven't tried newer versions yet.
> > >
> > > In terms of OSPM _OST behaviour, I am not sure if returning OST success
> > > status
> > > on succcesful removal is *required*. Figure 6-37, page 306 of ACPI spec5.0
> > > shows that on succcesfull OS ejection ejection, _EJ0 is evaluated.
> > > Evaluating
> > > _OST does not seem to be a requirement, is it? (cc'ing linux-acpi for
> > > input)
> > >
> > > In linux guests, on successful removal, _EJ0 is always evaluated. I
> > > believe we
> > > should be handling _EJ0 and doing the dimm removal (object_unparent)
> > > there.
> > > Currently OST successes are never received and dimm devices remain in
> > > QEMU even
> > > when successfully ejected from guest.
> > > E.g. a quick patch for _EJ0 handling, on top of Hu Tao's series:
> > >
> > > acpi, memory-hotplug: Add _EJ0 handling
> > >
> > > ---
> > > docs/specs/acpi_mem_hotplug.txt | 3 ++-
> > > hw/acpi/memory_hotplug.c | 13 +++++++------
> > > hw/i386/ssdt-misc.dsl | 3 ++-
> > > include/hw/acpi/memory_hotplug.h | 1 +
> > > 4 files changed, 12 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/docs/specs/acpi_mem_hotplug.txt
> > > b/docs/specs/acpi_mem_hotplug.txt
> > > index 1290994..1352962 100644
> > > --- a/docs/specs/acpi_mem_hotplug.txt
> > > +++ b/docs/specs/acpi_mem_hotplug.txt
> > > @@ -28,7 +28,8 @@ Memory hot-plug interface (IO port 0xa00-0xa17, 1-4
> > > byte access):
> > > region will read/store data from/to selected memory
> > > device.
> > > [0x4-0x7] OST event code reported by OSPM
> > > [0x8-0xb] OST status code reported by OSPM
> > > - [0xc-0x13] reserved, writes into it are ignored
> > > + [0xc] EJ device if written to
> > > + [0xd-0x13] reserved, writes into it are ignored
> > > [0x14] Memory device control fields
> > > bits:
> > > 0: reserved, OSPM must clear it before writing to register
> > > diff --git a/hw/acpi/memory_hotplug.c b/hw/acpi/memory_hotplug.c
> > > index 8aa829d..d3edd28 100644
> > > --- a/hw/acpi/memory_hotplug.c
> > > +++ b/hw/acpi/memory_hotplug.c
> > > @@ -93,9 +93,6 @@ static void acpi_memory_hotplug_write(void *opaque,
> > > hwaddr addr, uint64_t data,
> > > case 0x03: /* EJECT */
> > > switch (mdev->ost_status) {
> > > case 0x0: /* SUCCESS */
> > > - object_unparent(OBJECT(mdev->dimm));
> > > - mdev->is_removing = false;
> > > - mdev->dimm = NULL;
> > > break;
> > > case 0x1: /* FAILURE */
> > > case 0x2: /* UNRECOGNIZED NOTIFY */
> > > @@ -115,9 +112,6 @@ static void acpi_memory_hotplug_write(void *opaque,
> > > hwaddr addr, uint64_t data,
> > > case 0x103: /* OSPM EJECT */
> > > switch (mdev->ost_status) {
> > > case 0x0: /* SUCCESS */
> > > - object_unparent(OBJECT(mdev->dimm));
> > > - mdev->is_removing = false;
> > > - mdev->dimm = NULL;
> > > break;
> > > case 0x84: /* EJECTION IN PROGRESS */
> > > mdev->is_enabled = false;
> > > @@ -137,6 +131,12 @@ static void acpi_memory_hotplug_write(void *opaque,
> > > hwaddr addr, uint64_t data,
> > > mdev->is_enabled = false;
> > > }
> > > break;
> > > + case 0x0c:
> > > + mdev = &mem_st->devs[mem_st->selector];
> > > + object_unparent(OBJECT(mdev->dimm));
> > > + mdev->is_removing = false;
> > > + mdev->dimm = NULL;
> > > + break;
> > > }
> > > }
> > >
> > > @@ -238,6 +238,7 @@ static const VMStateDescription vmstate_memhp_sts = {
> > > VMSTATE_BOOL(is_inserting, MemStatus),
> > > VMSTATE_UINT32(ost_event, MemStatus),
> > > VMSTATE_UINT32(ost_status, MemStatus),
> > > + VMSTATE_UINT32(ej_status, MemStatus),
> > > VMSTATE_END_OF_LIST()
> > > }
> > > };
> > > diff --git a/hw/i386/ssdt-misc.dsl b/hw/i386/ssdt-misc.dsl
> > > index 927e503..d20c6f0 100644
> > > --- a/hw/i386/ssdt-misc.dsl
> > > +++ b/hw/i386/ssdt-misc.dsl
> > > @@ -163,6 +163,7 @@ DefinitionBlock ("ssdt-misc.aml", "SSDT", 0x01,
> > > "BXPC", "BXSSDTSUSP", 0x1)
> > > MSEL, 32, // DIMM selector, write only
> > > MOEV, 32, // _OST event code, write only
> > > MOSC, 32, // _OST status code, write only
> > > + MEJE, 8, // if written to, eject DIMM
> > > }
> > >
> > > Method(MESC, 0, Serialized) {
> > > @@ -283,7 +284,7 @@ DefinitionBlock ("ssdt-misc.aml", "SSDT", 0x01,
> > > "BXPC", "BXSSDTSUSP", 0x1)
> > > Method(MDEJ, 2) {
> > > Acquire(MLCK, 0xFFFF)
> > > Store(ToInteger(Arg0), MSEL) // select DIMM
> > > - Store(One, MRMV)
> > > + Store(1, MEJE)
> > Is there a reason to replace MRMV with MEJE and use whole byte instead of 1
> > bit field?
> > It could be used the same way as MEJE is used.
>
> I think the original intent of MRMV is for it to be a read-only field
> indicating the
> is_removing field of the memory hotplug hardware. So it's not the same
> semantics
> as MEJE, which is writable and means "remove the device, it's safe".
> But you are right that it could be a singlebit field.
The same register [0x14] is control register when writing there, so we can
use-reuse
the same bit position as MRMV for signaling QEMU to perform eject on writing 1
there,
similarly like it's done for insert event.
>
> thanks,
>
> - Vasilis
>
