Commit bf210f79 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

irq/s390: Add arch_is_isolated_msi() for s390 

s390 doesn't use irq_domains, so it has no place to set
IRQ_DOMAIN_FLAG_ISOLATED_MSI. Instead of continuing to abuse the iommu
subsystem to convey this information add a simple define which s390 can
make statically true. The define will cause msi_device_has_isolated() to
return true.

Remove IOMMU_CAP_INTR_REMAP from the s390 iommu driver.

Link: https://lore.kernel.org/r/8-v3-3313bb5dd3a3+10f11-secure_msi_jgg@nvidia.com


Reviewed-by: default avatarMatthew Rosato <mjrosato@linux.ibm.com>
Tested-by: default avatarMatthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent f188bdb5

arch/s390/include/asm/msi.h

0 → 100644
+17 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _ASM_S390_MSI_H

#define _ASM_S390_MSI_H

#include <asm-generic/msi.h>



/*

 * Work around S390 not using irq_domain at all so we can't set

 * IRQ_DOMAIN_FLAG_ISOLATED_MSI. See for an explanation how it works:

 *

 * https://lore.kernel.org/r/31af8174-35e9-ebeb-b9ef-74c90d4bfd93@linux.ibm.com/

 *

 * Note this is less isolated than the ARM/x86 versions as userspace can trigger

 * MSI belonging to kernel devices within the same gisa.

 */

#define arch_is_isolated_msi() true



#endif

drivers/iommu/s390-iommu.c

+0 −2
Original line number Diff line number Diff line
@@ -34,8 +34,6 @@ static bool s390_iommu_capable(struct device *dev, enum iommu_cap cap) 
	switch (cap) {

	case IOMMU_CAP_CACHE_COHERENCY:

		return true;

	case IOMMU_CAP_INTR_REMAP:

		return true;

	default:

		return false;

	}

include/linux/msi.h

+7 −3
Original line number Diff line number Diff line
@@ -48,6 +48,10 @@ typedef struct arch_msi_msg_data { 
} __attribute__ ((packed)) arch_msi_msg_data_t;

#endif



#ifndef arch_is_isolated_msi

#define arch_is_isolated_msi() false

#endif



/**

 * msi_msg - Representation of a MSI message

 * @address_lo:		Low 32 bits of msi message address
@@ -657,10 +661,10 @@ static inline bool msi_device_has_isolated_msi(struct device *dev) 
	/*

	 * Arguably if the platform does not enable MSI support then it has

	 * "isolated MSI", as an interrupt controller that cannot receive MSIs

	 * is inherently isolated by our definition. As nobody seems to needs

	 * this be conservative and return false anyhow.

	 * is inherently isolated by our definition. The default definition for

	 * arch_is_isolated_msi() is conservative and returns false anyhow.

	 */

	return false;

	return arch_is_isolated_msi();

}

#endif /* CONFIG_GENERIC_MSI_IRQ */

kernel/irq/msi.c

+1 −1
Original line number Diff line number Diff line
@@ -1647,6 +1647,6 @@ bool msi_device_has_isolated_msi(struct device *dev) 
	for (; domain; domain = domain->parent)

		if (domain->flags & IRQ_DOMAIN_FLAG_ISOLATED_MSI)

			return true;

	return false;

	return arch_is_isolated_msi();

}

EXPORT_SYMBOL_GPL(msi_device_has_isolated_msi);