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* [RFC PATCH 0/4] fix FF-A call failed with pKVM when ff-a driver is built-in
@ 2026-04-17 17:57 Yeoreum Yun
  2026-04-17 17:57 ` [RFC PATCH 1/4] security: ima: move ima_init into late_initcall_sync Yeoreum Yun
                   ` (3 more replies)
  0 siblings, 4 replies; 9+ messages in thread
From: Yeoreum Yun @ 2026-04-17 17:57 UTC (permalink / raw)
  To: linux-security-module, linux-kernel, linux-integrity,
	linux-arm-kernel, kvmarm
  Cc: paul, jmorris, serge, zohar, roberto.sassu, dmitry.kasatkin,
	eric.snowberg, peterhuewe, jarkko, jgg, sudeep.holla, maz, oupton,
	joey.gouly, suzuki.poulose, yuzenghui, catalin.marinas, will,
	Yeoreum Yun

commit 0e0546eabcd6 ("firmware: arm_ffa: Change initcall level of ffa_init() to rootfs_initcall")
changed the initcall level of ffa_init() to rootfs_initcall to address
an issue where IMA could not properly recognize the TPM device
when FF-A driver is built as built-in.

However, this introduces another problem: pKVM fails to handle FF-A calls
because it cannot trap the FFA_VERSION call invoked by ffa_init().

To ensure the TPM device is recognized when present in the system,
it is preferable to invoke ima_init() at a later stage.
Deferred probing is resolved by deferred_probe_initcall(),
which runs at the late_initcall level.
Therefore, introduce an LSM initcall at late_initcall_sync and
move ima_init() to this level.

With this change, revert the initcall level of ffa_init() back to
device_initcall. Additionally, to handle the case where ffa_init() runs
before kvm_init(), check whether pKVM has been initialized during ffa_init().
If not, defer initialization to prevent failures of FF-A calls
due to the inability to trap FFA_VERSION and FFA_RXTX_MAP in pKVM.

This patch is based on v7.0

Yeoreum Yun (4):
  security: ima: move ima_init into late_initcall_sync
  tpm: tpm_crb_ffa: revert defered_probed when tpm_crb_ffa is built-in
  firmware: arm_ffa: revert ffa_init() initcall level to device_initcall
  firmware: arm_ffa: check pkvm initailised when initailise ffa driver

 arch/arm64/kvm/arm.c              |  1 +
 drivers/char/tpm/tpm_crb_ffa.c    | 18 +++---------------
 drivers/firmware/arm_ffa/driver.c | 14 +++++++++++++-
 include/linux/lsm_hooks.h         |  2 ++
 security/integrity/ima/ima_main.c |  2 +-
 security/lsm_init.c               | 13 +++++++++++--
 6 files changed, 31 insertions(+), 19 deletions(-)


base-commit: 028ef9c96e96197026887c0f092424679298aae8
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}


^ permalink raw reply	[flat|nested] 9+ messages in thread

* [RFC PATCH 1/4] security: ima: move ima_init into late_initcall_sync
  2026-04-17 17:57 [RFC PATCH 0/4] fix FF-A call failed with pKVM when ff-a driver is built-in Yeoreum Yun
@ 2026-04-17 17:57 ` Yeoreum Yun
  2026-04-17 17:57 ` [RFC PATCH 2/4] tpm: tpm_crb_ffa: revert defered_probed when tpm_crb_ffa is built-in Yeoreum Yun
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 9+ messages in thread
From: Yeoreum Yun @ 2026-04-17 17:57 UTC (permalink / raw)
  To: linux-security-module, linux-kernel, linux-integrity,
	linux-arm-kernel, kvmarm
  Cc: paul, jmorris, serge, zohar, roberto.sassu, dmitry.kasatkin,
	eric.snowberg, peterhuewe, jarkko, jgg, sudeep.holla, maz, oupton,
	joey.gouly, suzuki.poulose, yuzenghui, catalin.marinas, will,
	Yeoreum Yun

To generate the boot_aggregate log in the IMA subsystem with TPM PCR values,
the TPM driver must be built as built-in and
must be probed before the IMA subsystem is initialized.

However, when the TPM device operates over the FF-A protocol using
the CRB interface, probing fails and returns -EPROBE_DEFER if
the tpm_crb_ffa device — an FF-A device that provides the communication
interface to the tpm_crb driver — has not yet been probed.

To ensure the TPM device operating over the FF-A protocol with
the CRB interface is probed before IMA initialization,
the following conditions must be met:

   1. The corresponding ffa_device must be registered,
      which is done via ffa_init().

   2. The tpm_crb_driver must successfully probe this device via
      tpm_crb_ffa_init().

   3. The tpm_crb driver using CRB over FF-A can then
      be probed successfully. (See crb_acpi_add() and
      tpm_crb_ffa_init() for reference.)

Unfortunately, ffa_init(), tpm_crb_ffa_init(), and crb_acpi_driver_init() are
all registered with device_initcall, which means crb_acpi_driver_init() may
be invoked before ffa_init() and tpm_crb_ffa_init() are completed.

When this occurs, probing the TPM device is deferred.
However, the deferred probe can happen after the IMA subsystem
has already been initialized, since IMA initialization is performed
during late_initcall, and deferred_probe_initcall() is performed
at the same level.

To resolve this, move ima_init() into late_inicall_sync level
so that let IMA not miss TPM PCR value when generating boot_aggregate
log though TPM device presents in the system.

Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 include/linux/lsm_hooks.h         |  2 ++
 security/integrity/ima/ima_main.c |  2 +-
 security/lsm_init.c               | 13 +++++++++++--
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index d48bf0ad26f4..88fe105b7f00 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -166,6 +166,7 @@ enum lsm_order {
  * @initcall_fs: LSM callback for fs_initcall setup, optional
  * @initcall_device: LSM callback for device_initcall() setup, optional
  * @initcall_late: LSM callback for late_initcall() setup, optional
+ * @initcall_late_sync: LSM callback for late_initcall_sync() setup, optional
  */
 struct lsm_info {
 	const struct lsm_id *id;
@@ -181,6 +182,7 @@ struct lsm_info {
 	int (*initcall_fs)(void);
 	int (*initcall_device)(void);
 	int (*initcall_late)(void);
+	int (*initcall_late_sync)(void);
 };

 #define DEFINE_LSM(lsm)							\
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 1d6229b156fb..ace280fa3212 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -1320,5 +1320,5 @@ DEFINE_LSM(ima) = {
 	.order = LSM_ORDER_LAST,
 	.blobs = &ima_blob_sizes,
 	/* Start IMA after the TPM is available */
-	.initcall_late = init_ima,
+	.initcall_late_sync = init_ima,
 };
diff --git a/security/lsm_init.c b/security/lsm_init.c
index 573e2a7250c4..4e5c59beb82a 100644
--- a/security/lsm_init.c
+++ b/security/lsm_init.c
@@ -547,13 +547,22 @@ device_initcall(security_initcall_device);
  * security_initcall_late - Run the LSM late initcalls
  */
 static int __init security_initcall_late(void)
+{
+	return lsm_initcall(late);
+}
+late_initcall(security_initcall_late);
+
+/**
+ * security_initcall_late_sync - Run the LSM late initcalls sync
+ */
+static int __init security_initcall_late_sync(void)
 {
 	int rc;

-	rc = lsm_initcall(late);
+	rc = lsm_initcall(late_sync);
 	lsm_pr_dbg("all enabled LSMs fully activated\n");
 	call_blocking_lsm_notifier(LSM_STARTED_ALL, NULL);

 	return rc;
 }
-late_initcall(security_initcall_late);
+late_initcall_sync(security_initcall_late_sync);
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [RFC PATCH 2/4] tpm: tpm_crb_ffa: revert defered_probed when tpm_crb_ffa is built-in
  2026-04-17 17:57 [RFC PATCH 0/4] fix FF-A call failed with pKVM when ff-a driver is built-in Yeoreum Yun
  2026-04-17 17:57 ` [RFC PATCH 1/4] security: ima: move ima_init into late_initcall_sync Yeoreum Yun
@ 2026-04-17 17:57 ` Yeoreum Yun
  2026-04-17 17:57 ` [RFC PATCH 3/4] firmware: arm_ffa: revert ffa_init() initcall level to device_initcall Yeoreum Yun
  2026-04-17 17:57 ` [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver Yeoreum Yun
  3 siblings, 0 replies; 9+ messages in thread
From: Yeoreum Yun @ 2026-04-17 17:57 UTC (permalink / raw)
  To: linux-security-module, linux-kernel, linux-integrity,
	linux-arm-kernel, kvmarm
  Cc: paul, jmorris, serge, zohar, roberto.sassu, dmitry.kasatkin,
	eric.snowberg, peterhuewe, jarkko, jgg, sudeep.holla, maz, oupton,
	joey.gouly, suzuki.poulose, yuzenghui, catalin.marinas, will,
	Yeoreum Yun

commit 746d9e9f62a6 ("tpm: tpm_crb_ffa: try to probe tpm_crb_ffa when it's build_in")
probe tpm_crb_ffa forcefully when it's built-in to integrate with IMA.

However, as IMA init function is changed to late_initcall_sync level.
So, this change isn't required anymore.

Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 drivers/char/tpm/tpm_crb_ffa.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c
index 99f1c1e5644b..025c4d4b17ca 100644
--- a/drivers/char/tpm/tpm_crb_ffa.c
+++ b/drivers/char/tpm/tpm_crb_ffa.c
@@ -177,23 +177,13 @@ static int tpm_crb_ffa_to_linux_errno(int errno)
  */
 int tpm_crb_ffa_init(void)
 {
-	int ret = 0;
-
-	if (!IS_MODULE(CONFIG_TCG_ARM_CRB_FFA)) {
-		ret = ffa_register(&tpm_crb_ffa_driver);
-		if (ret) {
-			tpm_crb_ffa = ERR_PTR(-ENODEV);
-			return ret;
-		}
-	}
-
 	if (!tpm_crb_ffa)
-		ret = -ENOENT;
+		return -ENOENT;

 	if (IS_ERR_VALUE(tpm_crb_ffa))
-		ret = -ENODEV;
+		return -ENODEV;

-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(tpm_crb_ffa_init);

@@ -405,9 +395,7 @@ static struct ffa_driver tpm_crb_ffa_driver = {
 	.id_table = tpm_crb_ffa_device_id,
 };

-#ifdef MODULE
 module_ffa_driver(tpm_crb_ffa_driver);
-#endif

 MODULE_AUTHOR("Arm");
 MODULE_DESCRIPTION("TPM CRB FFA driver");
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [RFC PATCH 3/4] firmware: arm_ffa: revert ffa_init() initcall level to device_initcall
  2026-04-17 17:57 [RFC PATCH 0/4] fix FF-A call failed with pKVM when ff-a driver is built-in Yeoreum Yun
  2026-04-17 17:57 ` [RFC PATCH 1/4] security: ima: move ima_init into late_initcall_sync Yeoreum Yun
  2026-04-17 17:57 ` [RFC PATCH 2/4] tpm: tpm_crb_ffa: revert defered_probed when tpm_crb_ffa is built-in Yeoreum Yun
@ 2026-04-17 17:57 ` Yeoreum Yun
  2026-04-17 17:57 ` [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver Yeoreum Yun
  3 siblings, 0 replies; 9+ messages in thread
From: Yeoreum Yun @ 2026-04-17 17:57 UTC (permalink / raw)
  To: linux-security-module, linux-kernel, linux-integrity,
	linux-arm-kernel, kvmarm
  Cc: paul, jmorris, serge, zohar, roberto.sassu, dmitry.kasatkin,
	eric.snowberg, peterhuewe, jarkko, jgg, sudeep.holla, maz, oupton,
	joey.gouly, suzuki.poulose, yuzenghui, catalin.marinas, will,
	Yeoreum Yun

commit 0e0546eabcd6 ("firmware: arm_ffa: Change initcall level of ffa_init() to rootfs_initcall")
changed the initcall level of ffa_init() to rootfs_initcall to address
an issue where IMA could not properly recognize the TPM device.

However, this introduces a problem: pKVM fails to handle any FF-A calls
because it cannot trap the FFA_VERSION call invoked by ffa_init().

Since the IMA init function level has been changed to late_initcall_sync,
there is no longer a need to keep ffa_init() at rootfs_initcall.
Revert it back to device_initcall.

Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 drivers/firmware/arm_ffa/driver.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index f2f94d4d533e..02c76ac1570b 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -2106,7 +2106,7 @@ static int __init ffa_init(void)
 	kfree(drv_info);
 	return ret;
 }
-rootfs_initcall(ffa_init);
+device_initcall(ffa_init);

 static void __exit ffa_exit(void)
 {
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver
  2026-04-17 17:57 [RFC PATCH 0/4] fix FF-A call failed with pKVM when ff-a driver is built-in Yeoreum Yun
                   ` (2 preceding siblings ...)
  2026-04-17 17:57 ` [RFC PATCH 3/4] firmware: arm_ffa: revert ffa_init() initcall level to device_initcall Yeoreum Yun
@ 2026-04-17 17:57 ` Yeoreum Yun
  2026-04-18  9:24   ` Marc Zyngier
  3 siblings, 1 reply; 9+ messages in thread
From: Yeoreum Yun @ 2026-04-17 17:57 UTC (permalink / raw)
  To: linux-security-module, linux-kernel, linux-integrity,
	linux-arm-kernel, kvmarm
  Cc: paul, jmorris, serge, zohar, roberto.sassu, dmitry.kasatkin,
	eric.snowberg, peterhuewe, jarkko, jgg, sudeep.holla, maz, oupton,
	joey.gouly, suzuki.poulose, yuzenghui, catalin.marinas, will,
	Yeoreum Yun

When pKVM is enabled, the FF-A driver must be initialized after pKVM.
Otherwise, pKVM cannot negotiate the FF-A version or
obtain RX/TX buffer information, leading to failures in FF-A calls.

During FF-A driver initialization, check whether pKVM has been initialized.
If not, defer probing of the FF-A driver.

Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
---
 arch/arm64/kvm/arm.c              |  1 +
 drivers/firmware/arm_ffa/driver.c | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 410ffd41fd73..0f517b1c05cd 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -119,6 +119,7 @@ bool is_kvm_arm_initialised(void)
 {
 	return kvm_arm_initialised;
 }
+EXPORT_SYMBOL(is_kvm_arm_initialised);

 int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 {
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index 02c76ac1570b..2647d6554afd 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -42,6 +42,8 @@
 #include <linux/uuid.h>
 #include <linux/xarray.h>

+#include <asm/virt.h>
+
 #include "common.h"

 #define FFA_DRIVER_VERSION	FFA_VERSION_1_2
@@ -2035,6 +2037,16 @@ static int __init ffa_init(void)
 	u32 buf_sz;
 	size_t rxtx_bufsz = SZ_4K;

+	/*
+	 * When pKVM is enabled, the FF-A driver must be initialized
+	 * after pKVM initialization. Otherwise, pKVM cannot negotiate
+	 * the FF-A version or obtain RX/TX buffer information,
+	 * which leads to failures in FF-A calls.
+	 */
+	if (IS_ENABLED(CONFIG_KVM) && is_protected_kvm_enabled() &&
+	    !is_kvm_arm_initialised())
+		return -EPROBE_DEFER;
+
 	ret = ffa_transport_init(&invoke_ffa_fn);
 	if (ret)
 		return ret;
--
LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* Re: [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver
  2026-04-17 17:57 ` [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver Yeoreum Yun
@ 2026-04-18  9:24   ` Marc Zyngier
  2026-04-18 10:34     ` Yeoreum Yun
  0 siblings, 1 reply; 9+ messages in thread
From: Marc Zyngier @ 2026-04-18  9:24 UTC (permalink / raw)
  To: Yeoreum Yun
  Cc: linux-security-module, linux-kernel, linux-integrity,
	linux-arm-kernel, kvmarm, paul, jmorris, serge, zohar,
	roberto.sassu, dmitry.kasatkin, eric.snowberg, peterhuewe, jarkko,
	jgg, sudeep.holla, oupton, joey.gouly, suzuki.poulose, yuzenghui,
	catalin.marinas, will

On Fri, 17 Apr 2026 18:57:59 +0100,
Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> 
> When pKVM is enabled, the FF-A driver must be initialized after pKVM.
> Otherwise, pKVM cannot negotiate the FF-A version or
> obtain RX/TX buffer information, leading to failures in FF-A calls.
> 
> During FF-A driver initialization, check whether pKVM has been initialized.
> If not, defer probing of the FF-A driver.
> 
> Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> ---
>  arch/arm64/kvm/arm.c              |  1 +
>  drivers/firmware/arm_ffa/driver.c | 12 ++++++++++++
>  2 files changed, 13 insertions(+)
> 
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 410ffd41fd73..0f517b1c05cd 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -119,6 +119,7 @@ bool is_kvm_arm_initialised(void)
>  {
>  	return kvm_arm_initialised;
>  }
> +EXPORT_SYMBOL(is_kvm_arm_initialised);

EXPORT_SYMBOL_GPL(), please.

> 
>  int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
>  {
> diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
> index 02c76ac1570b..2647d6554afd 100644
> --- a/drivers/firmware/arm_ffa/driver.c
> +++ b/drivers/firmware/arm_ffa/driver.c
> @@ -42,6 +42,8 @@
>  #include <linux/uuid.h>
>  #include <linux/xarray.h>
> 
> +#include <asm/virt.h>
> +
>  #include "common.h"
> 
>  #define FFA_DRIVER_VERSION	FFA_VERSION_1_2
> @@ -2035,6 +2037,16 @@ static int __init ffa_init(void)
>  	u32 buf_sz;
>  	size_t rxtx_bufsz = SZ_4K;
> 
> +	/*
> +	 * When pKVM is enabled, the FF-A driver must be initialized
> +	 * after pKVM initialization. Otherwise, pKVM cannot negotiate
> +	 * the FF-A version or obtain RX/TX buffer information,
> +	 * which leads to failures in FF-A calls.
> +	 */
> +	if (IS_ENABLED(CONFIG_KVM) && is_protected_kvm_enabled() &&
> +	    !is_kvm_arm_initialised())
> +		return -EPROBE_DEFER;
> +

That's still fundamentally wrong: pkvm is not ready until
finalize_pkvm() has finished, and that's not indicated by
is_kvm_arm_initialised().

	M.

-- 
Jazz isn't dead. It just smells funny.

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver
  2026-04-18  9:24   ` Marc Zyngier
@ 2026-04-18 10:34     ` Yeoreum Yun
  2026-04-19 10:41       ` Marc Zyngier
  0 siblings, 1 reply; 9+ messages in thread
From: Yeoreum Yun @ 2026-04-18 10:34 UTC (permalink / raw)
  To: Marc Zyngier
  Cc: linux-security-module, linux-kernel, linux-integrity,
	linux-arm-kernel, kvmarm, paul, jmorris, serge, zohar,
	roberto.sassu, dmitry.kasatkin, eric.snowberg, peterhuewe, jarkko,
	jgg, sudeep.holla, oupton, joey.gouly, suzuki.poulose, yuzenghui,
	catalin.marinas, will

Hi Marc,

> On Fri, 17 Apr 2026 18:57:59 +0100,
> Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> >
> > When pKVM is enabled, the FF-A driver must be initialized after pKVM.
> > Otherwise, pKVM cannot negotiate the FF-A version or
> > obtain RX/TX buffer information, leading to failures in FF-A calls.
> >
> > During FF-A driver initialization, check whether pKVM has been initialized.
> > If not, defer probing of the FF-A driver.
> >
> > Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> > ---
> >  arch/arm64/kvm/arm.c              |  1 +
> >  drivers/firmware/arm_ffa/driver.c | 12 ++++++++++++
> >  2 files changed, 13 insertions(+)
> >
> > diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> > index 410ffd41fd73..0f517b1c05cd 100644
> > --- a/arch/arm64/kvm/arm.c
> > +++ b/arch/arm64/kvm/arm.c
> > @@ -119,6 +119,7 @@ bool is_kvm_arm_initialised(void)
> >  {
> >  	return kvm_arm_initialised;
> >  }
> > +EXPORT_SYMBOL(is_kvm_arm_initialised);
>
> EXPORT_SYMBOL_GPL(), please.

Okay.

>
> >
> >  int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
> >  {
> > diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
> > index 02c76ac1570b..2647d6554afd 100644
> > --- a/drivers/firmware/arm_ffa/driver.c
> > +++ b/drivers/firmware/arm_ffa/driver.c
> > @@ -42,6 +42,8 @@
> >  #include <linux/uuid.h>
> >  #include <linux/xarray.h>
> >
> > +#include <asm/virt.h>
> > +
> >  #include "common.h"
> >
> >  #define FFA_DRIVER_VERSION	FFA_VERSION_1_2
> > @@ -2035,6 +2037,16 @@ static int __init ffa_init(void)
> >  	u32 buf_sz;
> >  	size_t rxtx_bufsz = SZ_4K;
> >
> > +	/*
> > +	 * When pKVM is enabled, the FF-A driver must be initialized
> > +	 * after pKVM initialization. Otherwise, pKVM cannot negotiate
> > +	 * the FF-A version or obtain RX/TX buffer information,
> > +	 * which leads to failures in FF-A calls.
> > +	 */
> > +	if (IS_ENABLED(CONFIG_KVM) && is_protected_kvm_enabled() &&
> > +	    !is_kvm_arm_initialised())
> > +		return -EPROBE_DEFER;
> > +
>
> That's still fundamentally wrong: pkvm is not ready until
> finalize_pkvm() has finished, and that's not indicated by
> is_kvm_arm_initialised().

Thanks. I miss the TSC bit set in here.
IMHO, I'd like to make an new state check function --
is_pkvm_arm_initialised() so that ff-a driver to know whether
pkvm is initialised.

or any other suggestion?

Thanks.

--
Sincerely,
Yeoreum Yun

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver
  2026-04-18 10:34     ` Yeoreum Yun
@ 2026-04-19 10:41       ` Marc Zyngier
  2026-04-19 11:12         ` Yeoreum Yun
  0 siblings, 1 reply; 9+ messages in thread
From: Marc Zyngier @ 2026-04-19 10:41 UTC (permalink / raw)
  To: Yeoreum Yun
  Cc: linux-security-module, linux-kernel, linux-integrity,
	linux-arm-kernel, kvmarm, paul, jmorris, serge, zohar,
	roberto.sassu, dmitry.kasatkin, eric.snowberg, peterhuewe, jarkko,
	jgg, sudeep.holla, oupton, joey.gouly, suzuki.poulose, yuzenghui,
	catalin.marinas, will

On Sat, 18 Apr 2026 11:34:30 +0100,
Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> 
> > > @@ -2035,6 +2037,16 @@ static int __init ffa_init(void)
> > >  	u32 buf_sz;
> > >  	size_t rxtx_bufsz = SZ_4K;
> > >
> > > +	/*
> > > +	 * When pKVM is enabled, the FF-A driver must be initialized
> > > +	 * after pKVM initialization. Otherwise, pKVM cannot negotiate
> > > +	 * the FF-A version or obtain RX/TX buffer information,
> > > +	 * which leads to failures in FF-A calls.
> > > +	 */
> > > +	if (IS_ENABLED(CONFIG_KVM) && is_protected_kvm_enabled() &&
> > > +	    !is_kvm_arm_initialised())
> > > +		return -EPROBE_DEFER;
> > > +
> >
> > That's still fundamentally wrong: pkvm is not ready until
> > finalize_pkvm() has finished, and that's not indicated by
> > is_kvm_arm_initialised().
> 
> Thanks. I miss the TSC bit set in here.

That's the least of the problems. None of the infrastructure is in
place at this stage...

> IMHO, I'd like to make an new state check function --
> is_pkvm_arm_initialised() so that ff-a driver to know whether
> pkvm is initialised.

Doesn't sound great, TBH.

> or any other suggestion?

Instead of adding more esoteric predicates, I'd rather you build on an
existing infrastructure. You have a dependency on KVM, use something
that is designed to enforce dependencies. Device links spring to mind
as something designed for that.

Can you look into enabling this for KVM? If that's possible, then it
should be easy enough to delay the actual KVM registration after pKVM
is finalised.

Thanks,

	M.

-- 
Jazz isn't dead. It just smells funny.

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver
  2026-04-19 10:41       ` Marc Zyngier
@ 2026-04-19 11:12         ` Yeoreum Yun
  0 siblings, 0 replies; 9+ messages in thread
From: Yeoreum Yun @ 2026-04-19 11:12 UTC (permalink / raw)
  To: Marc Zyngier
  Cc: linux-security-module, linux-kernel, linux-integrity,
	linux-arm-kernel, kvmarm, paul, jmorris, serge, zohar,
	roberto.sassu, dmitry.kasatkin, eric.snowberg, peterhuewe, jarkko,
	jgg, sudeep.holla, oupton, joey.gouly, suzuki.poulose, yuzenghui,
	catalin.marinas, will

Hi Marc,

> On Sat, 18 Apr 2026 11:34:30 +0100,
> Yeoreum Yun <yeoreum.yun@arm.com> wrote:
> >
> > > > @@ -2035,6 +2037,16 @@ static int __init ffa_init(void)
> > > >  	u32 buf_sz;
> > > >  	size_t rxtx_bufsz = SZ_4K;
> > > >
> > > > +	/*
> > > > +	 * When pKVM is enabled, the FF-A driver must be initialized
> > > > +	 * after pKVM initialization. Otherwise, pKVM cannot negotiate
> > > > +	 * the FF-A version or obtain RX/TX buffer information,
> > > > +	 * which leads to failures in FF-A calls.
> > > > +	 */
> > > > +	if (IS_ENABLED(CONFIG_KVM) && is_protected_kvm_enabled() &&
> > > > +	    !is_kvm_arm_initialised())
> > > > +		return -EPROBE_DEFER;
> > > > +
> > >
> > > That's still fundamentally wrong: pkvm is not ready until
> > > finalize_pkvm() has finished, and that's not indicated by
> > > is_kvm_arm_initialised().
> >
> > Thanks. I miss the TSC bit set in here.
>
> That's the least of the problems. None of the infrastructure is in
> place at this stage...
>
> > IMHO, I'd like to make an new state check function --
> > is_pkvm_arm_initialised() so that ff-a driver to know whether
> > pkvm is initialised.
>
> Doesn't sound great, TBH.
>
> > or any other suggestion?
>
> Instead of adding more esoteric predicates, I'd rather you build on an
> existing infrastructure. You have a dependency on KVM, use something
> that is designed to enforce dependencies. Device links spring to mind
> as something designed for that.
>
> Can you look into enabling this for KVM? If that's possible, then it
> should be easy enough to delay the actual KVM registration after pKVM
> is finalised.

or what about some event notifier? Just like:

----------&<-----------

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index b51ab6840f9c..ad038a3b8727 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -68,6 +68,8 @@
 #include <asm/sysreg.h>
 #include <asm/cpufeature.h>

+struct notifier_block;
+
 /*
  * __boot_cpu_mode records what mode CPUs were booted in.
  * A correctly-implemented bootloader must start all CPUs in the same mode:
@@ -166,6 +168,15 @@ static inline bool is_hyp_nvhe(void)
 	return is_hyp_mode_available() && !is_kernel_in_hyp_mode();
 }

+enum kvm_arm_event {
+	PKVM_INITIALISED,
+	KVM_ARM_EVENT_MAX,
+};
+
+extern int kvm_arm_event_notifier_call_chain(enum kvm_arm_event event, void *data);
+extern int kvm_arm_event_notifier_register(struct notifier_block *nb);
+extern int kvm_arm_event_notifier_unregister(struct notifier_block *nb);
+
 #endif /* __ASSEMBLER__ */

 #endif /* ! __ASM__VIRT_H */
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 410ffd41fd73..8da10049ab65 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -14,6 +14,7 @@
 #include <linux/vmalloc.h>
 #include <linux/fs.h>
 #include <linux/mman.h>
+#include <linux/notifier.h>
 #include <linux/sched.h>
 #include <linux/kvm.h>
 #include <linux/kvm_irqfd.h>
@@ -111,6 +112,8 @@ DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);

 DECLARE_KVM_NVHE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);

+BLOCKING_NOTIFIER_HEAD(kvm_arm_event_notifier_head);
+
 static bool vgic_present, kvm_arm_initialised;

 static DEFINE_PER_CPU(unsigned char, kvm_hyp_initialized);
@@ -3064,4 +3067,22 @@ enum kvm_mode kvm_get_mode(void)
 	return kvm_mode;
 }

+int kvm_arm_event_notifier_call_chain(enum kvm_arm_event event, void *data)
+{
+	return blocking_notifier_call_chain(&kvm_arm_event_notifier_head,
+					    event, data);
+}
+
+int kvm_arm_event_notifier_register(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&kvm_arm_event_notifier_head, nb);
+}
+EXPORT_SYMBOL_GPL(kvm_arm_event_notifier_register);
+
+int kvm_arm_event_notifier_unregister(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&kvm_arm_event_notifier_head, nb);
+}
+EXPORT_SYMBOL_GPL(kvm_arm_event_notifier_unregister);
+
 module_init(kvm_arm_init);
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index d7a0f69a9982..e76562b0a45a 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -280,6 +280,8 @@ static int __init finalize_pkvm(void)
 	ret = pkvm_drop_host_privileges();
 	if (ret)
 		pr_err("Failed to finalize Hyp protection: %d\n", ret);
+	else
+		kvm_arm_event_notifier_call_chain(PKVM_INITIALISED, NULL);

 	return ret;
 }
diff --git a/drivers/firmware/arm_ffa/common.h b/drivers/firmware/arm_ffa/common.h
index 9c6425a81d0d..5cdf4bd222c6 100644
--- a/drivers/firmware/arm_ffa/common.h
+++ b/drivers/firmware/arm_ffa/common.h
@@ -18,9 +18,9 @@ bool ffa_device_is_valid(struct ffa_device *ffa_dev);
 void ffa_device_match_uuid(struct ffa_device *ffa_dev, const uuid_t *uuid);

 #ifdef CONFIG_ARM_FFA_SMCCC
-int __init ffa_transport_init(ffa_fn **invoke_ffa_fn);
+int ffa_transport_init(ffa_fn **invoke_ffa_fn);
 #else
-static inline int __init ffa_transport_init(ffa_fn **invoke_ffa_fn)
+static inline int ffa_transport_init(ffa_fn **invoke_ffa_fn)
 {
 	return -EOPNOTSUPP;
 }
diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c
index 02c76ac1570b..67df053e65b8 100644
--- a/drivers/firmware/arm_ffa/driver.c
+++ b/drivers/firmware/arm_ffa/driver.c
@@ -35,6 +35,7 @@
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/mutex.h>
+#include <linux/notifier.h>
 #include <linux/of_irq.h>
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
@@ -42,6 +43,8 @@
 #include <linux/uuid.h>
 #include <linux/xarray.h>

+#include <asm/virt.h>
+
 #include "common.h"

 #define FFA_DRIVER_VERSION	FFA_VERSION_1_2
@@ -2029,7 +2032,7 @@ static void ffa_notifications_setup(void)
 	ffa_notifications_cleanup();
 }

-static int __init ffa_init(void)
+static int __ffa_init(void)
 {
 	int ret;
 	u32 buf_sz;
@@ -2105,11 +2108,42 @@ static int __init ffa_init(void)
 free_drv_info:
 	kfree(drv_info);
 	return ret;
+
+}
+
+static int ffa_kvm_arm_event_handler(struct notifier_block *nb,
+				     unsigned long event, void *unused)
+{
+	if (event == PKVM_INITIALISED)
+		__ffa_init();
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block ffa_kvm_arm_event_notifier = {
+	.notifier_call = ffa_kvm_arm_event_handler,
+};
+
+static int __init ffa_init(void)
+{
+	/*
+	 * When pKVM is enabled, the FF-A driver must be initialized
+	 * after pKVM initialization. Otherwise, pKVM cannot negotiate
+	 * the FF-A version or obtain RX/TX buffer information,
+	 * which leads to failures in FF-A calls.
+	 */
+	if (IS_ENABLED(CONFIG_KVM) && is_protected_kvm_enabled() &&
+	    !is_pkvm_initialized())
+		return kvm_arm_event_notifier_register(&ffa_kvm_arm_event_notifier);
+
+	return __ffa_init();
 }
 device_initcall(ffa_init);

 static void __exit ffa_exit(void)
 {
+	if (IS_ENABLED(CONFIG_KVM))
+		kvm_arm_event_notifier_unregister(&ffa_kvm_arm_event_notifier);
 	ffa_notifications_cleanup();
 	ffa_partitions_cleanup();
 	ffa_rxtx_unmap();
diff --git a/drivers/firmware/arm_ffa/smccc.c b/drivers/firmware/arm_ffa/smccc.c
index 4d85bfff0a4e..e6125dd9f58f 100644
--- a/drivers/firmware/arm_ffa/smccc.c
+++ b/drivers/firmware/arm_ffa/smccc.c
@@ -17,7 +17,7 @@ static void __arm_ffa_fn_hvc(ffa_value_t args, ffa_value_t *res)
 	arm_smccc_1_2_hvc(&args, res);
 }

-int __init ffa_transport_init(ffa_fn **invoke_ffa_fn)
+int ffa_transport_init(ffa_fn **invoke_ffa_fn)
 {
 	enum arm_smccc_conduit conduit;


> --
> Jazz isn't dead. It just smells funny.

--
Sincerely,
Yeoreum Yun

^ permalink raw reply related	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2026-04-19 11:12 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-04-17 17:57 [RFC PATCH 0/4] fix FF-A call failed with pKVM when ff-a driver is built-in Yeoreum Yun
2026-04-17 17:57 ` [RFC PATCH 1/4] security: ima: move ima_init into late_initcall_sync Yeoreum Yun
2026-04-17 17:57 ` [RFC PATCH 2/4] tpm: tpm_crb_ffa: revert defered_probed when tpm_crb_ffa is built-in Yeoreum Yun
2026-04-17 17:57 ` [RFC PATCH 3/4] firmware: arm_ffa: revert ffa_init() initcall level to device_initcall Yeoreum Yun
2026-04-17 17:57 ` [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver Yeoreum Yun
2026-04-18  9:24   ` Marc Zyngier
2026-04-18 10:34     ` Yeoreum Yun
2026-04-19 10:41       ` Marc Zyngier
2026-04-19 11:12         ` Yeoreum Yun

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