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2025-05-30KVM: arm64: vgic-debug: Avoid dereferencing NULL ITE pointerMarc Zyngier
Dan reports that iterating over a device ITEs can legitimately lead to a NULL pointer, and that the NULL check is placed *after* the pointer has already been dereferenced. Hoist the pointer check as early as possible and be done with it. Reported-by: Dan Carpenter <dan.carpenter@linaro.org> Fixes: 30deb51a677b ("KVM: arm64: vgic-its: Add debugfs interface to expose ITS tables") Link: https://lore.kernel.org/r/aDBylI1YnjPatAbr@stanley.mountain Cc: Jing Zhang <jingzhangos@google.com> Link: https://lore.kernel.org/r/20250530091647.1152489-1-maz@kernel.org Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-22KVM: arm64: Fix documentation for vgic_its_iter_next()Marc Zyngier
As reported by the build robot, the documentation for vgic_its_iter_next() contains a typo. Fix it. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202505221421.KAuWlmSr-lkp@intel.com/ Signed-off-by: Marc Zyngier <maz@kernel.org>
2025-05-19KVM: arm64: vgic-its: Add debugfs interface to expose ITS tablesJing Zhang
This commit introduces a debugfs interface to display the contents of the VGIC Interrupt Translation Service (ITS) tables. The ITS tables map Device/Event IDs to Interrupt IDs and target processors. Exposing this information through debugfs allows for easier inspection and debugging of the interrupt routing configuration. The debugfs interface presents the ITS table data in a tabular format: Device ID: 0x0, Event ID Range: [0 - 31] EVENT_ID INTID HWINTID TARGET COL_ID HW ----------------------------------------------- 0 8192 0 0 0 0 1 8193 0 0 0 0 2 8194 0 2 2 0 Device ID: 0x18, Event ID Range: [0 - 3] EVENT_ID INTID HWINTID TARGET COL_ID HW ----------------------------------------------- 0 8225 0 0 0 0 1 8226 0 1 1 0 2 8227 0 3 3 0 Device ID: 0x10, Event ID Range: [0 - 7] EVENT_ID INTID HWINTID TARGET COL_ID HW ----------------------------------------------- 0 8229 0 3 3 1 1 8230 0 0 0 1 2 8231 0 1 1 1 3 8232 0 2 2 1 4 8233 0 3 3 1 The output is generated using the seq_file interface, allowing for efficient handling of potentially large ITS tables. This interface is read-only and does not allow modification of the ITS tables. It is intended for debugging and informational purposes only. Signed-off-by: Jing Zhang <jingzhangos@google.com> Link: https://lore.kernel.org/r/20250220224247.2017205-1-jingzhangos@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-11-20KVM: arm64: vgic: Make vgic_get_irq() more robustMarc Zyngier
vgic_get_irq() has an awkward signature, as it takes both a kvm *and* a vcpu, where the vcpu is allowed to be NULL if the INTID being looked up is a global interrupt (SPI or LPI). This leads to potentially problematic situations where the INTID passed is a private interrupt, but that there is no vcpu. In order to make things less ambiguous, let have *two* helpers instead: - vgic_get_irq(struct kvm *kvm, u32 intid), which is only concerned with *global* interrupts, as indicated by the lack of vcpu. - vgic_get_vcpu_irq(struct kvm_vcpu *vcpu, u32 intid), which can return *any* interrupt class, but must have of course a non-NULL vcpu. Most of the code nicely falls under one or the other situations, except for a couple of cases (close to the UABI or in the debug code) where we have to distinguish between the two cases. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20241117165757.247686-3-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-08-19KVM: arm64: vgic-debug: Don't put unmarked LPIsZenghui Yu
If there were LPIs being mapped behind our back (i.e., between .start() and .stop()), we would put them at iter_unmark_lpis() without checking if they were actually *marked*, which is obviously not good. Switch to use the xa_for_each_marked() iterator to fix it. Cc: stable@vger.kernel.org Fixes: 85d3ccc8b75b ("KVM: arm64: vgic-debug: Use an xarray mark for debug iterator") Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240817101541.1664-1-yuzenghui@huawei.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-08-07KVM: arm64: vgic-debug: Exit the iterator properly w/o LPIZenghui Yu
In case the guest doesn't have any LPI, we previously relied on the iterator setting 'intid = nr_spis + VGIC_NR_PRIVATE_IRQS' && 'lpi_idx = 1' to exit the iterator. But it was broken with commit 85d3ccc8b75b ("KVM: arm64: vgic-debug: Use an xarray mark for debug iterator") -- the intid remains at 'nr_spis + VGIC_NR_PRIVATE_IRQS - 1', and we end up endlessly printing the last SPI's state. Consider that it's meaningless to search the LPI xarray and populate lpi_idx when there is no LPI, let's just skip the process for that case. The result is that * If there's no LPI, we focus on the intid and exit the iterator when it runs out of the valid SPI range. * Otherwise we keep the current logic and let the xarray drive the iterator. Fixes: 85d3ccc8b75b ("KVM: arm64: vgic-debug: Use an xarray mark for debug iterator") Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> Acked-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240807052024.2084-1-yuzenghui@huawei.com Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2024-04-25KVM: arm64: vgic-debug: Use an xarray mark for debug iteratorOliver Upton
The vgic debug iterator is the final user of vgic_copy_lpi_list(), but is a bit more complicated to transition to something else. Use a mark in the LPI xarray to record the indices 'known' to the debug iterator. Protect against the LPIs from being freed by associating an additional reference with the xarray mark. Rework iter_next() to let the xarray walk 'drive' the iteration after visiting all of the SGIs, PPIs, and SPIs. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240422200158.2606761-6-oliver.upton@linux.dev Signed-off-by: Marc Zyngier <maz@kernel.org>
2024-02-23KVM: arm64: vgic: Use atomics to count LPIsOliver Upton
Switch to using atomics for LPI accounting, allowing vgic_irq references to be dropped in parallel. Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20240221054253.3848076-7-oliver.upton@linux.dev Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2023-09-30KVM: arm64: vgic: Use vcpu_idx for the debug informationMarc Zyngier
When dumping the debug information, use vcpu_idx instead of vcpu_id, as this is independent of any userspace influence. Reviewed-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230927090911.3355209-6-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
2023-03-29KVM: arm64: Use config_lock to protect vgic stateOliver Upton
Almost all of the vgic state is VM-scoped but accessed from the context of a vCPU. These accesses were serialized on the kvm->lock which cannot be nested within a vcpu->mutex critical section. Move over the vgic state to using the config_lock. Tweak the lock ordering where necessary to ensure that the config_lock is acquired after the vcpu->mutex. Acquire the config_lock in kvm_vgic_create() to avoid a race between the converted flows and GIC creation. Where necessary, continue to acquire kvm->lock to avoid a race with vCPU creation (i.e. flows that use lock_all_vcpus()). Finally, promote the locking expectations in comments to lockdep assertions and update the locking documentation for the config_lock as well as vcpu->mutex. Cc: stable@vger.kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230327164747.2466958-5-oliver.upton@linux.dev
2022-04-06KVM: arm64: vgic: Remove unnecessary type castingsYu Zhe
Remove unnecessary casts. Signed-off-by: Yu Zhe <yuzhe@nfschina.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220329102059.268983-1-yuzhe@nfschina.com
2020-09-18KVM: arm64: vgic-debug: Convert to use DEFINE_SEQ_ATTRIBUTE macroLiu Shixin
Use DEFINE_SEQ_ATTRIBUTE macro to simplify the code. Signed-off-by: Liu Shixin <liushixin2@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200916025023.3992679-1-liushixin2@huawei.com
2020-05-16KVM: arm64: Move virt/kvm/arm to arch/arm64Marc Zyngier
Now that the 32bit KVM/arm host is a distant memory, let's move the whole of the KVM/arm64 code into the arm64 tree. As they said in the song: Welcome Home (Sanitarium). Signed-off-by: Marc Zyngier <maz@kernel.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20200513104034.74741-1-maz@kernel.org