[RFC PATCH 0/4] fix FF-A call failed with pKVM when ff-a driver is built-in

[RFC PATCH 0/4] fix FF-A call failed with pKVM when ff-a driver is built-in

[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}

[RFC PATCH 1/4] security: ima: move ima_init into late_initcall_sync

[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}

[RFC PATCH 2/4] tpm: tpm_crb_ffa: revert defered_probed when tpm_crb_ffa is built-in

[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}

[RFC PATCH 3/4] firmware: arm_ffa: revert ffa_init() initcall level to device_initcall

[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}

[RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver

[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}

Re: [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver

[Marc Zyngier]

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.

Re: [RFC PATCH 4/4] firmware: arm_ffa: check pkvm initailised when initailise ffa driver

[Yeoreum Yun]

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