kernel/linux.git/virt/kvm/arm, branch v5.4.232

KVM: arm64: vgic: Fix exit condition in scan_its_table()

2022-10-29T08:20:35+00:00

commit c000a2607145d28b06c697f968491372ea56c23a upstream. With some PCIe topologies, restoring a guest fails while parsing the ITS device tables. Reproducer hints: 1. Create ARM virt VM with pxb-pcie bus which adds extra host bridges, with qemu command like: ``` -device pxb-pcie,bus_nr=8,id=pci.x,numa_node=0,bus=pcie.0 \ -device pcie-root-port,..,bus=pci.x \ ... -device pxb-pcie,bus_nr=37,id=pci.y,numa_node=1,bus=pcie.0 \ -device pcie-root-port,..,bus=pci.y \ ... ``` 2. Ensure the guest uses 2-level device table 3. Perform VM migration which calls save/restore device tables In that setup, we get a big "offset" between 2 device_ids, which makes unsigned "len" round up a big positive number, causing the scan loop to continue with a bad GPA. For example: 1. L1 table has 2 entries; 2. and we are now scanning at L2 table entry index 2075 (pointed to by L1 first entry) 3. if next device id is 9472, we will get a big offset: 7397; 4. with unsigned 'len', 'len -= offset * esz', len will underflow to a positive number, mistakenly into next iteration with a bad GPA; (It should break out of the current L2 table scanning, and jump into the next L1 table entry) 5. that bad GPA fails the guest read. Fix it by stopping the L2 table scan when the next device id is outside of the current table, allowing the scan to continue from the next L1 table entry. Thanks to Eric Auger for the fix suggestion. Fixes: 920a7a8fa92a ("KVM: arm64: vgic-its: Add infrastructure for tableookup") Suggested-by: Eric Auger Signed-off-by: Eric Ren [maz: commit message tidy-up] Signed-off-by: Marc Zyngier Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/d9c3a564af9e2c5bf63f48a7dcbf08cd593c5c0b.1665802985.git.renzhengeek@gmail.com Signed-off-by: Greg Kroah-Hartman

KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated

2022-03-19T12:40:15+00:00

commit a5905d6af492ee6a4a2205f0d550b3f931b03d03 upstream. KVM allows the guest to discover whether the ARCH_WORKAROUND SMCCC are implemented, and to preserve that state during migration through its firmware register interface. Add the necessary boiler plate for SMCCC_ARCH_WORKAROUND_3. Reviewed-by: Russell King (Oracle) Reviewed-by: Catalin Marinas [ kvm code moved to virt/kvm/arm. ] Signed-off-by: James Morse Signed-off-by: Sasha Levin

KVM: arm64: Handle PSCI resets before userspace touches vCPU state

2021-09-22T10:26:45+00:00

[ Upstream commit 6826c6849b46aaa91300201213701eb861af4ba0 ] The CPU_ON PSCI call takes a payload that KVM uses to configure a destination vCPU to run. This payload is non-architectural state and not exposed through any existing UAPI. Effectively, we have a race between CPU_ON and userspace saving/restoring a guest: if the target vCPU isn't ran again before the VMM saves its state, the requested PC and context ID are lost. When restored, the target vCPU will be runnable and start executing at its old PC. We can avoid this race by making sure the reset payload is serviced before userspace can access a vCPU's state. Fixes: 358b28f09f0a ("arm/arm64: KVM: Allow a VCPU to fully reset itself") Signed-off-by: Oliver Upton Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210818202133.1106786-3-oupton@google.com Signed-off-by: Sasha Levin

KVM: arm/arm64: Fix KVM_VGIC_V3_ADDR_TYPE_REDIST read

2021-06-23T12:41:31+00:00

commit 94ac0835391efc1a30feda6fc908913ec012951e upstream. When reading the base address of the a REDIST region through KVM_VGIC_V3_ADDR_TYPE_REDIST we expect the redistributor region list to be populated with a single element. However list_first_entry() expects the list to be non empty. Instead we should use list_first_entry_or_null which effectively returns NULL if the list is empty. Fixes: dbd9733ab674 ("KVM: arm/arm64: Replace the single rdist region by a list") Cc: # v4.18+ Signed-off-by: Eric Auger Reported-by: Gavin Shan Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210412150034.29185-1-eric.auger@redhat.com Signed-off-by: Greg Kroah-Hartman

KVM: arm64: Initialize VCPU mdcr_el2 before loading it

2021-05-22T09:38:30+00:00

commit 263d6287da1433aba11c5b4046388f2cdf49675c upstream. When a VCPU is created, the kvm_vcpu struct is initialized to zero in kvm_vm_ioctl_create_vcpu(). On VHE systems, the first time vcpu.arch.mdcr_el2 is loaded on hardware is in vcpu_load(), before it is set to a sensible value in kvm_arm_setup_debug() later in the run loop. The result is that KVM executes for a short time with MDCR_EL2 set to zero. This has several unintended consequences: * Setting MDCR_EL2.HPMN to 0 is constrained unpredictable according to ARM DDI 0487G.a, page D13-3820. The behavior specified by the architecture in this case is for the PE to behave as if MDCR_EL2.HPMN is set to a value less than or equal to PMCR_EL0.N, which means that an unknown number of counters are now disabled by MDCR_EL2.HPME, which is zero. * The host configuration for the other debug features controlled by MDCR_EL2 is temporarily lost. This has been harmless so far, as Linux doesn't use the other fields, but that might change in the future. Let's avoid both issues by initializing the VCPU's mdcr_el2 field in kvm_vcpu_vcpu_first_run_init(), thus making sure that the MDCR_EL2 register has a consistent value after each vcpu_load(). Fixes: d5a21bcc2995 ("KVM: arm64: Move common VHE/non-VHE trap config in separate functions") Signed-off-by: Alexandru Elisei Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20210407144857.199746-3-alexandru.elisei@arm.com Signed-off-by: Greg Kroah-Hartman

KVM: arm64: Ensure I-cache isolation between vcpus of a same VM

2021-03-17T16:03:57+00:00

Commit 01dc9262ff5797b675c32c0c6bc682777d23de05 upstream. It recently became apparent that the ARMv8 architecture has interesting rules regarding attributes being used when fetching instructions if the MMU is off at Stage-1. In this situation, the CPU is allowed to fetch from the PoC and allocate into the I-cache (unless the memory is mapped with the XN attribute at Stage-2). If we transpose this to vcpus sharing a single physical CPU, it is possible for a vcpu running with its MMU off to influence another vcpu running with its MMU on, as the latter is expected to fetch from the PoU (and self-patching code doesn't flush below that level). In order to solve this, reuse the vcpu-private TLB invalidation code to apply the same policy to the I-cache, nuking it every time the vcpu runs on a physical CPU that ran another vcpu of the same VM in the past. This involve renaming __kvm_tlb_flush_local_vmid() to __kvm_flush_cpu_context(), and inserting a local i-cache invalidation there. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier Acked-by: Will Deacon Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/20210303164505.68492-1-maz@kernel.org [maz: added 32bit ARM support] Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman

KVM: arm64: Fix exclusive limit for IPA size

2021-03-17T16:03:57+00:00

commit 262b003d059c6671601a19057e9fe1a5e7f23722 upstream. When registering a memslot, we check the size and location of that memslot against the IPA size to ensure that we can provide guest access to the whole of the memory. Unfortunately, this check rejects memslot that end-up at the exact limit of the addressing capability for a given IPA size. For example, it refuses the creation of a 2GB memslot at 0x8000000 with a 32bit IPA space. Fix it by relaxing the check to accept a memslot reaching the limit of the IPA space. Fixes: c3058d5da222 ("arm/arm64: KVM: Ensure memslots are within KVM_PHYS_SIZE") Reviewed-by: Eric Auger Signed-off-by: Marc Zyngier Cc: stable@vger.kernel.org Reviewed-by: Andrew Jones Link: https://lore.kernel.org/r/20210311100016.3830038-3-maz@kernel.org Signed-off-by: Greg Kroah-Hartman

KVM: arm64: vgic-v3: Drop the reporting of GICR_TYPER.Last for userspace

2020-12-02T07:49:46+00:00

commit 23bde34771f1ea92fb5e6682c0d8c04304d34b3b upstream. It was recently reported that if GICR_TYPER is accessed before the RD base address is set, we'll suffer from the unset @rdreg dereferencing. Oops... gpa_t last_rdist_typer = rdreg->base + GICR_TYPER + (rdreg->free_index - 1) * KVM_VGIC_V3_REDIST_SIZE; It's "expected" that users will access registers in the redistributor if the RD has been properly configured (e.g., the RD base address is set). But it hasn't yet been covered by the existing documentation. Per discussion on the list [1], the reporting of the GICR_TYPER.Last bit for userspace never actually worked. And it's difficult for us to emulate it correctly given that userspace has the flexibility to access it any time. Let's just drop the reporting of the Last bit for userspace for now (userspace should have full knowledge about it anyway) and it at least prevents kernel from panic ;-) [1] https://lore.kernel.org/kvmarm/c20865a267e44d1e2c0d52ce4e012263@kernel.org/ Fixes: ba7b3f1275fd ("KVM: arm/arm64: Revisit Redistributor TYPER last bit computation") Reported-by: Keqian Zhu Signed-off-by: Zenghui Yu Signed-off-by: Marc Zyngier Reviewed-by: Eric Auger Link: https://lore.kernel.org/r/20201117151629.1738-1-yuzenghui@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

KVM: arm64: ARM_SMCCC_ARCH_WORKAROUND_1 doesn't return SMCCC_RET_NOT_REQUIRED

2020-11-18T18:20:21+00:00

commit 1de111b51b829bcf01d2e57971f8fd07a665fa3f upstream. According to the SMCCC spec[1](7.5.2 Discovery) the ARM_SMCCC_ARCH_WORKAROUND_1 function id only returns 0, 1, and SMCCC_RET_NOT_SUPPORTED. 0 is "workaround required and safe to call this function" 1 is "workaround not required but safe to call this function" SMCCC_RET_NOT_SUPPORTED is "might be vulnerable or might not be, who knows, I give up!" SMCCC_RET_NOT_SUPPORTED might as well mean "workaround required, except calling this function may not work because it isn't implemented in some cases". Wonderful. We map this SMC call to 0 is SPECTRE_MITIGATED 1 is SPECTRE_UNAFFECTED SMCCC_RET_NOT_SUPPORTED is SPECTRE_VULNERABLE For KVM hypercalls (hvc), we've implemented this function id to return SMCCC_RET_NOT_SUPPORTED, 0, and SMCCC_RET_NOT_REQUIRED. One of those isn't supposed to be there. Per the code we call arm64_get_spectre_v2_state() to figure out what to return for this feature discovery call. 0 is SPECTRE_MITIGATED SMCCC_RET_NOT_REQUIRED is SPECTRE_UNAFFECTED SMCCC_RET_NOT_SUPPORTED is SPECTRE_VULNERABLE Let's clean this up so that KVM tells the guest this mapping: 0 is SPECTRE_MITIGATED 1 is SPECTRE_UNAFFECTED SMCCC_RET_NOT_SUPPORTED is SPECTRE_VULNERABLE Note: SMCCC_RET_NOT_AFFECTED is 1 but isn't part of the SMCCC spec Fixes: c118bbb52743 ("arm64: KVM: Propagate full Spectre v2 workaround state to KVM guests") Signed-off-by: Stephen Boyd Acked-by: Marc Zyngier Acked-by: Will Deacon Cc: Andre Przywara Cc: Steven Price Cc: Marc Zyngier Cc: stable@vger.kernel.org Link: https://developer.arm.com/documentation/den0028/latest [1] Link: https://lore.kernel.org/r/20201023154751.1973872-1-swboyd@chromium.org Signed-off-by: Will Deacon Signed-off-by: Stephen Boyd Signed-off-by: Greg Kroah-Hartman

KVM: arm64: Force PTE mapping on fault resulting in a device mapping

2020-11-18T18:20:15+00:00

[ Upstream commit 91a2c34b7d6fadc9c5d9433c620ea4c32ee7cae8 ] VFIO allows a device driver to resolve a fault by mapping a MMIO range. This can be subsequently result in user_mem_abort() to try and compute a huge mapping based on the MMIO pfn, which is a sure recipe for things to go wrong. Instead, force a PTE mapping when the pfn faulted in has a device mapping. Fixes: 6d674e28f642 ("KVM: arm/arm64: Properly handle faulting of device mappings") Suggested-by: Marc Zyngier Signed-off-by: Santosh Shukla [maz: rewritten commit message] Signed-off-by: Marc Zyngier Reviewed-by: Gavin Shan Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1603711447-11998-2-git-send-email-sashukla@nvidia.com Signed-off-by: Sasha Levin