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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [XENBUS PATCH] Add forced unplug support
On 09/07/2025 17:47, Tu Dinh wrote:
> Forced unplug aims to simplify driver servicing by, as its name implies,
> forcefully unplugging emulated devices when a driver is present, rather
> than when it's active.
>
> Create a Registry key at CurrentControlSet\XEN\ForceUnplug. Drivers can
> opt into forced unplug by creating an appropriate value (DISKS/NICS)
> in this key.
>
> Older drivers are not affected.
>
> Signed-off-by: Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx>
> ---
> Opting into forced unplug is totally optional. But it has the advantage
> of not needing multiple reboots, and avoids situations where both the
> emulated and PV drivers are running at the same time.
This is broken in case the xenfilt\Parameters\Active* values are deleted
(or otherwise not present).
> ---
> src/xen/driver.c | 79 ++++++++++++++++++++++++++++++++++++++----------
> src/xen/driver.h | 5 +++
> src/xen/unplug.c | 13 ++++++--
> 3 files changed, 79 insertions(+), 18 deletions(-)
>
> diff --git a/src/xen/driver.c b/src/xen/driver.c
> index b44753c..7b2621b 100644
> --- a/src/xen/driver.c
> +++ b/src/xen/driver.c
> @@ -63,6 +63,7 @@ typedef struct _XEN_DRIVER {
> PLOG_DISPOSITION QemuDisposition;
> HANDLE ParametersKey;
> HANDLE UnplugKey;
> + HANDLE ForceUnplugKey;
> HANDLE MemoryKey;
> } XEN_DRIVER, *PXEN_DRIVER;
>
> @@ -144,6 +145,30 @@ DriverGetUnplugKey(
> return __DriverGetUnplugKey();
> }
>
> +static FORCEINLINE VOID
> +__DriverSetForceUnplugKey(
> + _In_opt_ HANDLE Key
> + )
> +{
> + Driver.ForceUnplugKey = Key;
> +}
> +
> +static FORCEINLINE HANDLE
> +__DriverGetForceUnplugKey(
> + VOID
> + )
> +{
> + return Driver.ForceUnplugKey;
> +}
> +
> +HANDLE
> +DriverGetForceUnplugKey(
> + VOID
> + )
> +{
> + return __DriverGetForceUnplugKey();
> +}
> +
> static FORCEINLINE VOID
> __DriverSetMemoryKey(
> _In_opt_ HANDLE Key
> @@ -500,6 +525,7 @@ DllInitialize(
> HANDLE ServiceKey;
> HANDLE ParametersKey;
> HANDLE UnplugKey;
> + HANDLE ForceUnplugKey;
> HANDLE MemoryKey;
> LOG_LEVEL LogLevel;
> NTSTATUS status;
> @@ -577,12 +603,21 @@ DllInitialize(
>
> __DriverSetUnplugKey(UnplugKey);
>
> + status = RegistryCreateSubKey(ServiceKey,
> + "ForceUnplug",
> + REG_OPTION_NON_VOLATILE,
> + &ForceUnplugKey);
> + if (!NT_SUCCESS(status))
> + goto fail6;
> +
> + __DriverSetForceUnplugKey(ForceUnplugKey);
> +
> status = RegistryCreateSubKey(ServiceKey,
> "Memory",
> REG_OPTION_VOLATILE,
> &MemoryKey);
> if (!NT_SUCCESS(status))
> - goto fail6;
> + goto fail7;
>
> __DriverSetMemoryKey(MemoryKey);
>
> @@ -590,27 +625,27 @@ DllInitialize(
>
> status = AcpiInitialize();
> if (!NT_SUCCESS(status))
> - goto fail7;
> + goto fail8;
>
> status = SystemInitialize();
> if (!NT_SUCCESS(status))
> - goto fail8;
> + goto fail9;
>
> status = BugCheckInitialize();
> if (!NT_SUCCESS(status))
> - goto fail9;
> + goto fail10;
>
> status = ModuleInitialize();
> if (!NT_SUCCESS(status))
> - goto fail10;
> + goto fail11;
>
> status = ProcessInitialize();
> if (!NT_SUCCESS(status))
> - goto fail11;
> + goto fail12;
>
> status = UnplugInitialize();
> if (!NT_SUCCESS(status))
> - goto fail12;
> + goto fail13;
>
> RegistryCloseKey(ServiceKey);
>
> @@ -618,39 +653,45 @@ DllInitialize(
>
> return STATUS_SUCCESS;
>
> +fail13:
> + Error("fail13\n");
> +
> + ProcessTeardown();
> +
> fail12:
> Error("fail12\n");
>
> - ProcessTeardown();
> + ModuleTeardown();
>
> fail11:
> Error("fail11\n");
>
> - ModuleTeardown();
> + BugCheckTeardown();
>
> fail10:
> Error("fail10\n");
>
> - BugCheckTeardown();
> + SystemTeardown();
>
> fail9:
> Error("fail9\n");
>
> - SystemTeardown();
> + AcpiTeardown();
>
> fail8:
> Error("fail8\n");
>
> - AcpiTeardown();
> -
> -fail7:
> - Error("fail7\n");
> -
> HypercallTeardown();
>
> RegistryCloseKey(MemoryKey);
> __DriverSetMemoryKey(NULL);
>
> +fail7:
> + Error("fail7\n");
> +
> + RegistryCloseKey(ForceUnplugKey);
> + __DriverSetForceUnplugKey(NULL);
> +
> fail6:
> Error("fail6\n");
>
> @@ -698,6 +739,7 @@ DllUnload(
> )
> {
> HANDLE MemoryKey;
> + HANDLE ForceUnplugKey;
> HANDLE UnplugKey;
> HANDLE ParametersKey;
>
> @@ -722,6 +764,11 @@ DllUnload(
> RegistryCloseKey(MemoryKey);
> __DriverSetMemoryKey(NULL);
>
> + ForceUnplugKey = __DriverGetForceUnplugKey();
> +
> + RegistryCloseKey(ForceUnplugKey);
> + __DriverSetForceUnplugKey(NULL);
> +
> UnplugKey = __DriverGetUnplugKey();
>
> RegistryCloseKey(UnplugKey);
> diff --git a/src/xen/driver.h b/src/xen/driver.h
> index 21df779..6851e01 100644
> --- a/src/xen/driver.h
> +++ b/src/xen/driver.h
> @@ -43,6 +43,11 @@ DriverGetUnplugKey(
> VOID
> );
>
> +extern HANDLE
> +DriverGetForceUnplugKey(
> + VOID
> + );
> +
> extern PMDL
> DriverGetNamedPages(
> _In_ PSTR Name,
> diff --git a/src/xen/unplug.c b/src/xen/unplug.c
> index dbd9a2e..282ed93 100644
> --- a/src/xen/unplug.c
> +++ b/src/xen/unplug.c
> @@ -266,6 +266,7 @@ UnplugSetRequest(
> {
> PUNPLUG_CONTEXT Context = &UnplugContext;
> HANDLE UnplugKey;
> + HANDLE ForceUnplugKey;
> PSTR ValueName;
> PSTR EnumName;
> ULONG Value;
> @@ -277,6 +278,7 @@ UnplugSetRequest(
> ASSERT3U(KeGetCurrentIrql(), ==, PASSIVE_LEVEL);
>
> UnplugKey = DriverGetUnplugKey();
> + ForceUnplugKey = DriverGetForceUnplugKey();
>
> switch (Type) {
> case UNPLUG_DISKS:
> @@ -293,17 +295,24 @@ UnplugSetRequest(
> ASSERT(FALSE);
> }
>
> + status = RegistryQueryDwordValue(ForceUnplugKey,
> + ValueName,
> + &Value);
> + if (NT_SUCCESS(status) && Value)
> + goto unplug;
> +
> status = RegistryQueryDwordValue(UnplugKey,
> ValueName,
> &Value);
> if (!NT_SUCCESS(status))
> goto done;
>
> - (VOID) RegistryDeleteValue(UnplugKey, ValueName);
> -
> if (Value != 0)
> (VOID) UnplugCheckEnumKey(EnumName, &Value);
>
> +unplug:
> + (VOID) RegistryDeleteValue(UnplugKey, ValueName);
> +
> Info("%s (%u)\n", ValueName, Value);
>
> AcquireHighLock(&Context->Lock, &Irql);
Ngoc Tu Dinh | Vates XCP-ng Developer
XCP-ng & Xen Orchestra - Vates solutions
web: https://vates.tech
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