<Resend with some extra lists added to the Cc>
According to the mailing list discussion [1] about the preferred approach
for notifying hypervisor/VMM about guest entering s2idle state this RFC was
implemented.
Instead of original hypercall based approach, which involves KVM change [2]
and makes it hypervisor specific, implement different mechanism, which
takes advantage of MMIO/PIO trapping and makes it hypervisor independent.
For the RFCv1 [3]:
Patch #1 extends S2Idle ops by new notify handler which will be invoked as a
very last command before system actually enters S2Idle states. It also allows
to register and use driver specific notification hook which is used in
patch #2.
Patch #2 introduces new driver for virtual PMC, which registers
acpi_s2idle_dev_ops's notify handler. Its implementation is based on an
ACPI _DSM evaluation, which in turn can perform MMIO access and allow to
trap and therefore notify the VMM about guest entering S2Idle state.
For the RFCv2: the patch #1 was dropped as in the meantime Mario Limonciello
introduced a very similar patch [4] which uses s/notify/check and invokes the
callback a bit earlier just before s2idle_entry. Mentioned patch has already
been merged.
This patchset is marked as RFC since patch #2 implements driver for non
existing device "HYPE0001", which ACPI ID was not registered yet.
Furthermore the required registration process [5] will not be started
before getting positive feedback about this patchset.
[1] https://patchwork.kernel.org/project/linux-pm/patch/[email protected]/
[2] https://patchwork.kernel.org/project/linux-pm/patch/[email protected]/
[3] https://patchwork.kernel.org/project/linux-pm/cover/[email protected]/
[4] https://patchwork.kernel.org/project/linux-pm/patch/[email protected]
[5] https://uefi.org/PNP_ACPI_Registry
Grzegorz Jaszczyk (1):
platform/x86: Add virtual PMC driver used for S2Idle
drivers/platform/x86/Kconfig | 7 ++++
drivers/platform/x86/Makefile | 3 ++
drivers/platform/x86/virt_pmc.c | 73 +++++++++++++++++++++++++++++++++
3 files changed, 83 insertions(+)
create mode 100644 drivers/platform/x86/virt_pmc.c
--
2.39.1.519.gcb327c4b5f-goog
Virtual PMC driver is meant for the guest VMs for the S2Idle
notification. Its purpose is to register S2Idle dev ops check handler,
which will evaluate ACPI _DSM just before the guest enters S2Idle power
state.
This allows to trap on MMIO access done as a consequence of _DSM
evaluation and therefore notify the VMM about the guest entering S2Idle
state.
Signed-off-by: Grzegorz Jaszczyk <[email protected]>
---
Changelog v1..v2:
- Take advantage of acpi_s2idle_dev_ops's check() instead of notify()
---
drivers/platform/x86/Kconfig | 7 ++++
drivers/platform/x86/Makefile | 3 ++
drivers/platform/x86/virt_pmc.c | 73 +++++++++++++++++++++++++++++++++
3 files changed, 83 insertions(+)
create mode 100644 drivers/platform/x86/virt_pmc.c
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 5692385e2d26..b7c3f98031d7 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1099,6 +1099,13 @@ config WINMATE_FM07_KEYS
buttons below the display. This module adds an input device
that delivers key events when these buttons are pressed.
+config VIRT_PMC
+ tristate "Virt PMC"
+ depends on ACPI && SUSPEND
+ help
+ The Virtual PMC driver is meant for the guest VMs and its main
+ purpose is to notify about guest entering s2idle state.
+
endif # X86_PLATFORM_DEVICES
config P2SB
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 1d3d1b02541b..c4d3056cf4ea 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -129,6 +129,9 @@ obj-$(CONFIG_INTEL_SCU_WDT) += intel_scu_wdt.o
obj-$(CONFIG_INTEL_SCU_IPC_UTIL) += intel_scu_ipcutil.o
obj-$(CONFIG_X86_INTEL_LPSS) += pmc_atom.o
+# Virtual PMC
+obj-$(CONFIG_VIRT_PMC) += virt_pmc.o
+
# Siemens Simatic Industrial PCs
obj-$(CONFIG_SIEMENS_SIMATIC_IPC) += simatic-ipc.o
diff --git a/drivers/platform/x86/virt_pmc.c b/drivers/platform/x86/virt_pmc.c
new file mode 100644
index 000000000000..daf9c9ed86e5
--- /dev/null
+++ b/drivers/platform/x86/virt_pmc.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Virtual Power Management Controller Driver
+ *
+ * Author: Grzegorz Jaszczyk <[email protected]>
+ */
+
+#include <linux/acpi.h>
+#include <linux/platform_device.h>
+
+#define ACPI_VIRT_PMC_DSM_UUID "9ea49ba3-434a-49a6-be30-37cc55c4d397"
+#define ACPI_VIRT_PMC_NOTIFY 1
+
+static acpi_handle virt_pmc_handle;
+
+static void virt_pmc_s2idle_notify(void)
+{
+ union acpi_object *out_obj;
+ static guid_t dsm_guid;
+
+ guid_parse(ACPI_VIRT_PMC_DSM_UUID, &dsm_guid);
+
+ out_obj = acpi_evaluate_dsm(virt_pmc_handle, &dsm_guid,
+ 0, ACPI_VIRT_PMC_NOTIFY, NULL);
+
+ acpi_handle_debug(virt_pmc_handle, "_DSM function %u evaluation %s\n",
+ ACPI_VIRT_PMC_NOTIFY, out_obj ? "successful" : "failed");
+
+ ACPI_FREE(out_obj);
+}
+
+static struct acpi_s2idle_dev_ops amd_pmc_s2idle_dev_ops = {
+ .check = virt_pmc_s2idle_notify,
+};
+
+static int virt_pmc_probe(struct platform_device *pdev)
+{
+ int err = 0;
+
+ virt_pmc_handle = ACPI_HANDLE(&pdev->dev);
+
+ err = acpi_register_lps0_dev(&amd_pmc_s2idle_dev_ops);
+ if (err)
+ dev_warn(&pdev->dev, "failed to register LPS0 sleep handler\n");
+
+ return err;
+}
+
+static int virt_pmc_remove(struct platform_device *pdev)
+{
+ acpi_unregister_lps0_dev(&amd_pmc_s2idle_dev_ops);
+
+ return 0;
+}
+
+static const struct acpi_device_id virt_pmc_acpi_ids[] = {
+ {"HYPE0001", 0}, /* _HID for XXX Power Engine, _CID PNP0D80*/
+ { }
+};
+MODULE_DEVICE_TABLE(acpi, virt_pmc_acpi_ids);
+
+static struct platform_driver virt_pmc_driver = {
+ .driver = {
+ .name = "virtual_pmc",
+ .acpi_match_table = ACPI_PTR(virt_pmc_acpi_ids),
+ },
+ .probe = virt_pmc_probe,
+ .remove = virt_pmc_remove,
+};
+
+module_platform_driver(virt_pmc_driver);
+
+MODULE_DESCRIPTION("Virtual PMC Driver");
--
2.39.1.519.gcb327c4b5f-goog
On Thu, Feb 09 2023 at 15:21, Grzegorz Jaszczyk wrote:
> +
> +static struct acpi_s2idle_dev_ops amd_pmc_s2idle_dev_ops = {
What is AMD specific about this?
> + .check = virt_pmc_s2idle_notify,
> +};
...
> +
> +MODULE_DESCRIPTION("Virtual PMC Driver");
Lacks MODULE_LICENSE("GPL")
Thanks,
tglx
[AMD Official Use Only - General]
> -----Original Message-----
> From: Grzegorz Jaszczyk <[email protected]>
> Sent: Thursday, February 9, 2023 09:21
> To: [email protected]; [email protected]
> Cc: [email protected]; [email protected]; [email protected];
> [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; Limonciello, Mario <[email protected]>; linux-
> [email protected]; [email protected]; [email protected];
> Grzegorz Jaszczyk <[email protected]>
> Subject: [RESEND RFCv2 1/1] platform/x86: Add virtual PMC driver used for
> S2Idle
>
> Virtual PMC driver is meant for the guest VMs for the S2Idle
> notification. Its purpose is to register S2Idle dev ops check handler,
> which will evaluate ACPI _DSM just before the guest enters S2Idle power
> state.
>
> This allows to trap on MMIO access done as a consequence of _DSM
> evaluation and therefore notify the VMM about the guest entering S2Idle
> state.
>
> Signed-off-by: Grzegorz Jaszczyk <[email protected]>
> ---
> Changelog v1..v2:
> - Take advantage of acpi_s2idle_dev_ops's check() instead of notify()
> ---
> drivers/platform/x86/Kconfig | 7 ++++
> drivers/platform/x86/Makefile | 3 ++
> drivers/platform/x86/virt_pmc.c | 73
> +++++++++++++++++++++++++++++++++
> 3 files changed, 83 insertions(+)
> create mode 100644 drivers/platform/x86/virt_pmc.c
>
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 5692385e2d26..b7c3f98031d7 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -1099,6 +1099,13 @@ config WINMATE_FM07_KEYS
> buttons below the display. This module adds an input device
> that delivers key events when these buttons are pressed.
>
> +config VIRT_PMC
> + tristate "Virt PMC"
> + depends on ACPI && SUSPEND
> + help
> + The Virtual PMC driver is meant for the guest VMs and its main
> + purpose is to notify about guest entering s2idle state.
> +
> endif # X86_PLATFORM_DEVICES
>
> config P2SB
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index 1d3d1b02541b..c4d3056cf4ea 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -129,6 +129,9 @@ obj-$(CONFIG_INTEL_SCU_WDT) +=
> intel_scu_wdt.o
> obj-$(CONFIG_INTEL_SCU_IPC_UTIL) += intel_scu_ipcutil.o
> obj-$(CONFIG_X86_INTEL_LPSS) += pmc_atom.o
>
> +# Virtual PMC
> +obj-$(CONFIG_VIRT_PMC) += virt_pmc.o
> +
> # Siemens Simatic Industrial PCs
> obj-$(CONFIG_SIEMENS_SIMATIC_IPC) += simatic-ipc.o
>
> diff --git a/drivers/platform/x86/virt_pmc.c
> b/drivers/platform/x86/virt_pmc.c
> new file mode 100644
> index 000000000000..daf9c9ed86e5
> --- /dev/null
> +++ b/drivers/platform/x86/virt_pmc.c
> @@ -0,0 +1,73 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Virtual Power Management Controller Driver
> + *
> + * Author: Grzegorz Jaszczyk <[email protected]>
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/platform_device.h>
> +
> +#define ACPI_VIRT_PMC_DSM_UUID "9ea49ba3-434a-49a6-be30-
> 37cc55c4d397"
> +#define ACPI_VIRT_PMC_NOTIFY 1
> +
> +static acpi_handle virt_pmc_handle;
> +
> +static void virt_pmc_s2idle_notify(void)
> +{
> + union acpi_object *out_obj;
> + static guid_t dsm_guid;
> +
> + guid_parse(ACPI_VIRT_PMC_DSM_UUID, &dsm_guid);
> +
> + out_obj = acpi_evaluate_dsm(virt_pmc_handle, &dsm_guid,
> + 0, ACPI_VIRT_PMC_NOTIFY, NULL);
> +
> + acpi_handle_debug(virt_pmc_handle, "_DSM function %u
> evaluation %s\n",
> + ACPI_VIRT_PMC_NOTIFY, out_obj ? "successful" :
> "failed");
> +
> + ACPI_FREE(out_obj);
> +}
> +
> +static struct acpi_s2idle_dev_ops amd_pmc_s2idle_dev_ops = {
> + .check = virt_pmc_s2idle_notify,
> +};
> +
> +static int virt_pmc_probe(struct platform_device *pdev)
> +{
> + int err = 0;
> +
> + virt_pmc_handle = ACPI_HANDLE(&pdev->dev);
> +
> + err = acpi_register_lps0_dev(&amd_pmc_s2idle_dev_ops);
> + if (err)
> + dev_warn(&pdev->dev, "failed to register LPS0 sleep
> handler\n");
> +
Besides registering, I would think you also want to have a query to the
_DSM to determine what functions are available. It could allow this to
scale better if you're going to need to introduce a new function again
later for a different reason.
> + return err;
> +}
> +
> +static int virt_pmc_remove(struct platform_device *pdev)
> +{
> + acpi_unregister_lps0_dev(&amd_pmc_s2idle_dev_ops);
> +
> + return 0;
> +}
> +
> +static const struct acpi_device_id virt_pmc_acpi_ids[] = {
> + {"HYPE0001", 0}, /* _HID for XXX Power Engine, _CID PNP0D80*/
> + { }
> +};
> +MODULE_DEVICE_TABLE(acpi, virt_pmc_acpi_ids);
> +
> +static struct platform_driver virt_pmc_driver = {
> + .driver = {
> + .name = "virtual_pmc",
> + .acpi_match_table = ACPI_PTR(virt_pmc_acpi_ids),
> + },
> + .probe = virt_pmc_probe,
> + .remove = virt_pmc_remove,
> +};
> +
> +module_platform_driver(virt_pmc_driver);
> +
> +MODULE_DESCRIPTION("Virtual PMC Driver");
> --
> 2.39.1.519.gcb327c4b5f-goog
On Thu, Feb 09, 2023, Grzegorz Jaszczyk wrote:
> Virtual PMC driver is meant for the guest VMs for the S2Idle
> notification. Its purpose is to register S2Idle dev ops check handler,
> which will evaluate ACPI _DSM just before the guest enters S2Idle power
> state.
>
> This allows to trap on MMIO access done as a consequence of _DSM
> evaluation and therefore notify the VMM about the guest entering S2Idle
> state.
>
> Signed-off-by: Grzegorz Jaszczyk <[email protected]>
> ---
> Changelog v1..v2:
> - Take advantage of acpi_s2idle_dev_ops's check() instead of notify()
> ---
> drivers/platform/x86/Kconfig | 7 ++++
> drivers/platform/x86/Makefile | 3 ++
> drivers/platform/x86/virt_pmc.c | 73 +++++++++++++++++++++++++++++++++
> 3 files changed, 83 insertions(+)
> create mode 100644 drivers/platform/x86/virt_pmc.c
>
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 5692385e2d26..b7c3f98031d7 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -1099,6 +1099,13 @@ config WINMATE_FM07_KEYS
> buttons below the display. This module adds an input device
> that delivers key events when these buttons are pressed.
>
> +config VIRT_PMC
> + tristate "Virt PMC"
Maybe spell out "Virtual Power Management Controller"? See below.
> + depends on ACPI && SUSPEND
I think it makes sense to take a dependency on HYPERVISOR_GUEST. It's not strictly
required, but taking that dependency helps clarify that this is a guest-side thing,
e.g. "virtual PMC" in KVM-land means "virtual performance monitoring counter".
And IMO, disabling HYPERVISOR_GUEST should disable these type of guest-specific
features.
czw., 9 lut 2023 o 19:05 Thomas Gleixner <[email protected]> napisał(a):
>
> On Thu, Feb 09 2023 at 15:21, Grzegorz Jaszczyk wrote:
> > +
> > +static struct acpi_s2idle_dev_ops amd_pmc_s2idle_dev_ops = {
>
> What is AMD specific about this?
Nothing, my bad - I will remove the 'amd' prefix.
>
> > + .check = virt_pmc_s2idle_notify,
> > +};
>
> ...
>
> > +
> > +MODULE_DESCRIPTION("Virtual PMC Driver");
>
> Lacks MODULE_LICENSE("GPL")
Sure,
Thank you
>
> Thanks,
>
> tglx
czw., 9 lut 2023 o 19:25 Limonciello, Mario
<[email protected]> napisał(a):
>
> [AMD Official Use Only - General]
>
>
>
> > -----Original Message-----
> > From: Grzegorz Jaszczyk <[email protected]>
> > Sent: Thursday, February 9, 2023 09:21
> > To: [email protected]; [email protected]
> > Cc: [email protected]; [email protected]; [email protected];
> > [email protected]; [email protected];
> > [email protected]; [email protected]; [email protected];
> > [email protected]; Limonciello, Mario <[email protected]>; linux-
> > [email protected]; [email protected]; [email protected];
> > Grzegorz Jaszczyk <[email protected]>
> > Subject: [RESEND RFCv2 1/1] platform/x86: Add virtual PMC driver used for
> > S2Idle
> >
> > Virtual PMC driver is meant for the guest VMs for the S2Idle
> > notification. Its purpose is to register S2Idle dev ops check handler,
> > which will evaluate ACPI _DSM just before the guest enters S2Idle power
> > state.
> >
> > This allows to trap on MMIO access done as a consequence of _DSM
> > evaluation and therefore notify the VMM about the guest entering S2Idle
> > state.
> >
> > Signed-off-by: Grzegorz Jaszczyk <[email protected]>
> > ---
> > Changelog v1..v2:
> > - Take advantage of acpi_s2idle_dev_ops's check() instead of notify()
> > ---
> > drivers/platform/x86/Kconfig | 7 ++++
> > drivers/platform/x86/Makefile | 3 ++
> > drivers/platform/x86/virt_pmc.c | 73
> > +++++++++++++++++++++++++++++++++
> > 3 files changed, 83 insertions(+)
> > create mode 100644 drivers/platform/x86/virt_pmc.c
> >
> > diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> > index 5692385e2d26..b7c3f98031d7 100644
> > --- a/drivers/platform/x86/Kconfig
> > +++ b/drivers/platform/x86/Kconfig
> > @@ -1099,6 +1099,13 @@ config WINMATE_FM07_KEYS
> > buttons below the display. This module adds an input device
> > that delivers key events when these buttons are pressed.
> >
> > +config VIRT_PMC
> > + tristate "Virt PMC"
> > + depends on ACPI && SUSPEND
> > + help
> > + The Virtual PMC driver is meant for the guest VMs and its main
> > + purpose is to notify about guest entering s2idle state.
> > +
> > endif # X86_PLATFORM_DEVICES
> >
> > config P2SB
> > diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> > index 1d3d1b02541b..c4d3056cf4ea 100644
> > --- a/drivers/platform/x86/Makefile
> > +++ b/drivers/platform/x86/Makefile
> > @@ -129,6 +129,9 @@ obj-$(CONFIG_INTEL_SCU_WDT) +=
> > intel_scu_wdt.o
> > obj-$(CONFIG_INTEL_SCU_IPC_UTIL) += intel_scu_ipcutil.o
> > obj-$(CONFIG_X86_INTEL_LPSS) += pmc_atom.o
> >
> > +# Virtual PMC
> > +obj-$(CONFIG_VIRT_PMC) += virt_pmc.o
> > +
> > # Siemens Simatic Industrial PCs
> > obj-$(CONFIG_SIEMENS_SIMATIC_IPC) += simatic-ipc.o
> >
> > diff --git a/drivers/platform/x86/virt_pmc.c
> > b/drivers/platform/x86/virt_pmc.c
> > new file mode 100644
> > index 000000000000..daf9c9ed86e5
> > --- /dev/null
> > +++ b/drivers/platform/x86/virt_pmc.c
> > @@ -0,0 +1,73 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Virtual Power Management Controller Driver
> > + *
> > + * Author: Grzegorz Jaszczyk <[email protected]>
> > + */
> > +
> > +#include <linux/acpi.h>
> > +#include <linux/platform_device.h>
> > +
> > +#define ACPI_VIRT_PMC_DSM_UUID "9ea49ba3-434a-49a6-be30-
> > 37cc55c4d397"
> > +#define ACPI_VIRT_PMC_NOTIFY 1
> > +
> > +static acpi_handle virt_pmc_handle;
> > +
> > +static void virt_pmc_s2idle_notify(void)
> > +{
> > + union acpi_object *out_obj;
> > + static guid_t dsm_guid;
> > +
> > + guid_parse(ACPI_VIRT_PMC_DSM_UUID, &dsm_guid);
> > +
> > + out_obj = acpi_evaluate_dsm(virt_pmc_handle, &dsm_guid,
> > + 0, ACPI_VIRT_PMC_NOTIFY, NULL);
> > +
> > + acpi_handle_debug(virt_pmc_handle, "_DSM function %u
> > evaluation %s\n",
> > + ACPI_VIRT_PMC_NOTIFY, out_obj ? "successful" :
> > "failed");
> > +
> > + ACPI_FREE(out_obj);
> > +}
> > +
> > +static struct acpi_s2idle_dev_ops amd_pmc_s2idle_dev_ops = {
> > + .check = virt_pmc_s2idle_notify,
> > +};
> > +
> > +static int virt_pmc_probe(struct platform_device *pdev)
> > +{
> > + int err = 0;
> > +
> > + virt_pmc_handle = ACPI_HANDLE(&pdev->dev);
> > +
> > + err = acpi_register_lps0_dev(&amd_pmc_s2idle_dev_ops);
> > + if (err)
> > + dev_warn(&pdev->dev, "failed to register LPS0 sleep
> > handler\n");
> > +
>
> Besides registering, I would think you also want to have a query to the
> _DSM to determine what functions are available. It could allow this to
> scale better if you're going to need to introduce a new function again
> later for a different reason.
>
Ok, I will add such a query. Thanks
czw., 9 lut 2023 o 22:26 Sean Christopherson <[email protected]> napisał(a):
>
> On Thu, Feb 09, 2023, Grzegorz Jaszczyk wrote:
> > Virtual PMC driver is meant for the guest VMs for the S2Idle
> > notification. Its purpose is to register S2Idle dev ops check handler,
> > which will evaluate ACPI _DSM just before the guest enters S2Idle power
> > state.
> >
> > This allows to trap on MMIO access done as a consequence of _DSM
> > evaluation and therefore notify the VMM about the guest entering S2Idle
> > state.
> >
> > Signed-off-by: Grzegorz Jaszczyk <[email protected]>
> > ---
> > Changelog v1..v2:
> > - Take advantage of acpi_s2idle_dev_ops's check() instead of notify()
> > ---
> > drivers/platform/x86/Kconfig | 7 ++++
> > drivers/platform/x86/Makefile | 3 ++
> > drivers/platform/x86/virt_pmc.c | 73 +++++++++++++++++++++++++++++++++
> > 3 files changed, 83 insertions(+)
> > create mode 100644 drivers/platform/x86/virt_pmc.c
> >
> > diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> > index 5692385e2d26..b7c3f98031d7 100644
> > --- a/drivers/platform/x86/Kconfig
> > +++ b/drivers/platform/x86/Kconfig
> > @@ -1099,6 +1099,13 @@ config WINMATE_FM07_KEYS
> > buttons below the display. This module adds an input device
> > that delivers key events when these buttons are pressed.
> >
> > +config VIRT_PMC
> > + tristate "Virt PMC"
>
> Maybe spell out "Virtual Power Management Controller"? See below.
Sure, it makes sense to be more verbose here.
>
> > + depends on ACPI && SUSPEND
>
> I think it makes sense to take a dependency on HYPERVISOR_GUEST. It's not strictly
> required, but taking that dependency helps clarify that this is a guest-side thing,
> e.g. "virtual PMC" in KVM-land means "virtual performance monitoring counter".
>
> And IMO, disabling HYPERVISOR_GUEST should disable these type of guest-specific
> features.
Ok, thank you