- 29 Mar, 2022 7 commits
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Paolo Bonzini authored
Add a file to document all the different ways in which the virtual CPU emulation is imperfect. Include an example to show how to document such errata. Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com> Reviewed-by:
Jim Mattson <jmattson@google.com> Reviewed-by:
Oliver Upton <oupton@google.com> Message-Id: <20220322110712.222449-3-pbonzini@redhat.com> Signed-off-by:
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Paolo Bonzini authored
ARM already has an arm/ subdirectory, but s390 and x86 do not even though they have a relatively large number of files specific to them. Create new directories in Documentation/virt/kvm for these two architectures as well. While at it, group the API documentation and the developer documentation in the table of contents. Signed-off-by:
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Paolo Bonzini authored
kvm->mn_invalidate_lock and kvm->slots_arch_lock were not included in the documentation, add them. Signed-off-by:
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Paolo Bonzini authored
Separate the various locks clearly, and include the new names of blocked_vcpu_on_cpu_lock and blocked_vcpu_on_cpu. Signed-off-by:
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Nathan Chancellor authored
Clang warns: arch/x86/kvm/cpuid.c:739:2: error: unannotated fall-through between switch labels [-Werror,-Wimplicit-fallthrough] default: ^ arch/x86/kvm/cpuid.c:739:2: note: insert 'break;' to avoid fall-through default: ^ break; 1 error generated. Clang is a little more pedantic than GCC, which does not warn when falling through to a case that is just break or return. Clang's version is more in line with the kernel's own stance in deprecated.rst, which states that all switch/case blocks must end in either break, fallthrough, continue, goto, or return. Add the missing break to silence the warning. Fixes: f144c49e ("KVM: x86: synthesize CPUID leaf 0x80000021h if useful") Reported-by:kernel test robot <lkp@intel.com> Signed-off-by:
Nathan Chancellor <nathan@kernel.org> Message-Id: <20220322152906.112164-1-nathan@kernel.org> Signed-off-by:
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David Matlack authored
This reverts commit 3d3aab1b. Now that the KVM module's lifetime is tied to kvm.users_count, there is no need to also tie it's lifetime to the lifetime of the VM and vCPU file descriptors. Suggested-by:
Sean Christopherson <seanjc@google.com> Signed-off-by:
David Matlack <dmatlack@google.com> Message-Id: <20220303183328.1499189-3-dmatlack@google.com> Reviewed-by:
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David Matlack authored
Tie the lifetime the KVM module to the lifetime of each VM via kvm.users_count. This way anything that grabs a reference to the VM via kvm_get_kvm() cannot accidentally outlive the KVM module. Prior to this commit, the lifetime of the KVM module was tied to the lifetime of /dev/kvm file descriptors, VM file descriptors, and vCPU file descriptors by their respective file_operations "owner" field. This approach is insufficient because references grabbed via kvm_get_kvm() do not prevent closing any of the aforementioned file descriptors. This fixes a long standing theoretical bug in KVM that at least affects async page faults. kvm_setup_async_pf() grabs a reference via kvm_get_kvm(), and drops it in an asynchronous work callback. Nothing prevents the VM file descriptor from being closed and the KVM module from being unloaded before this callback runs. Fixes: af585b92 ("KVM: Halt vcpu if page it tries to access is swapped out") Fixes: 3d3aab1b ("KVM: set owner of cpu and vm file operations") Cc: stable@vger.kernel.org Suggested-by:
Ben Gardon <bgardon@google.com> [ Based on a patch from Ben implemented for Google's kernel. ] Signed-off-by:
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- 21 Mar, 2022 8 commits
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Paolo Bonzini authored
Instead of using array_size, use a function that takes care of the multiplication. While at it, switch to kvcalloc since this allocation should not be very large. Signed-off-by: -
Oliver Upton authored
KVM_CAP_DISABLE_QUIRKS is irrevocably broken. The capability does not advertise the set of quirks which may be disabled to userspace, so it is impossible to predict the behavior of KVM. Worse yet, KVM_CAP_DISABLE_QUIRKS will tolerate any value for cap->args[0], meaning it fails to reject attempts to set invalid quirk bits. The only valid workaround for the quirky quirks API is to add a new CAP. Actually advertise the set of quirks that can be disabled to userspace so it can predict KVM's behavior. Reject values for cap->args[0] that contain invalid bits. Finally, add documentation for the new capability and describe the existing quirks. Signed-off-by:
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Thomas Gleixner authored
Non constant TSC is a nightmare on bare metal already, but with virtualization it becomes a complete disaster because the workarounds are horrible latency wise. That's also a preliminary for running RT in a guest on top of a RT host. Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Message-Id: <Yh5eJSG19S2sjZfy@linutronix.de> Signed-off-by:
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Paolo Bonzini authored
Guests X86_BUG_NULL_SEG if and only if the host has them. Use the info from static_cpu_has_bug to form the 0x80000021 CPUID leaf that was defined for Zen3. Userspace can then set the bit even on older CPUs that do not have the bug, such as Zen2. Do the same for X86_FEATURE_LFENCE_RDTSC as well, since various processors have had very different ways of detecting it and not all of them are available to userspace. Signed-off-by: -
Paolo Bonzini authored
CPUID leaf 0x80000021 defines some features (or lack of bugs) of AMD processors. Expose the ones that make sense via KVM_GET_SUPPORTED_CPUID. Signed-off-by: -
Maxim Levitsky authored
KVM_X86_OP_OPTIONAL_RET0 can only be used with 32-bit return values on 32-bit systems, because unsigned long is only 32-bits wide there and 64-bit values are returned in edx:eax. Reported-by:
Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by:
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Paolo Bonzini authored
This reverts commit cf3e2642. Multi-vCPU Hyper-V guests started crashing randomly on boot with the latest kvm/queue and the problem can be bisected the problem to this particular patch. Basically, I'm not able to boot e.g. 16-vCPU guest successfully anymore. Both Intel and AMD seem to be affected. Reverting the commit saves the day. Reported-by:
Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by:
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Paolo Bonzini authored
Since "KVM: x86/mmu: Zap only TDP MMU leafs in kvm_zap_gfn_range()" is going to be reverted, it's not going to be true anymore that the zap-page flow does not free any 'struct kvm_mmu_page'. Introduce an early flush before tdp_mmu_zap_leafs() returns, to preserve bisectability. Signed-off-by:
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- 18 Mar, 2022 3 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarmPaolo Bonzini authored
KVM/arm64 updates for 5.18 - Proper emulation of the OSLock feature of the debug architecture - Scalibility improvements for the MMU lock when dirty logging is on - New VMID allocator, which will eventually help with SVA in VMs - Better support for PMUs in heterogenous systems - PSCI 1.1 support, enabling support for SYSTEM_RESET2 - Implement CONFIG_DEBUG_LIST at EL2 - Make CONFIG_ARM64_ERRATUM_2077057 default y - Reduce the overhead of VM exit when no interrupt is pending - Remove traces of 32bit ARM host support from the documentation - Updated vgic selftests - Various cleanups, doc updates and spelling fixes
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Julia Lawall authored
Various spelling mistakes in comments. Detected with the help of Coccinelle. Signed-off-by:
Julia Lawall <Julia.Lawall@inria.fr> Signed-off-by:
Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220318103729.157574-24-Julia.Lawall@inria.fr
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Marc Zyngier authored
We currently deal with a set of booleans for VM features, while they could be better represented as set of flags contained in an unsigned long, similarily to what we are doing on the CPU side. Signed-off-by:
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- 15 Mar, 2022 2 commits
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https://github.com/kvm-riscv/linuxPaolo Bonzini authored
KVM/riscv changes for 5.18 - Prevent KVM_COMPAT from being selected - Refine __kvm_riscv_switch_to() implementation - RISC-V SBI v0.3 support
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Paolo Bonzini authored
Merge tag 'kvm-s390-next-5.18-2' of https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD KVM: s390: Fix, test and feature for 5.18 part 2 - memop selftest - fix SCK locking - adapter interruptions virtualization for secure guests
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- 14 Mar, 2022 6 commits
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Janis Schoetterl-Glausch authored
Test that errors occur if key protection disallows access, including tests for storage and fetch protection override. Perform tests for both logical vcpu and absolute vm ioctls. Also extend the existing tests to the vm ioctl. Signed-off-by:
Janis Schoetterl-Glausch <scgl@linux.ibm.com> Link: https://lore.kernel.org/r/20220308125841.3271721-6-scgl@linux.ibm.comSigned-off-by:
Christian Borntraeger <borntraeger@linux.ibm.com>
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Janis Schoetterl-Glausch authored
Do not just test the actual copy, but also that success is indicated when using the check only flag. Add copy test with storage key checking enabled, including tests for storage and fetch protection override. These test cover both logical vcpu ioctls as well as absolute vm ioctls. Signed-off-by:
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Janis Schoetterl-Glausch authored
The stages synchronize guest and host execution. This helps the reader and constraits the execution of the test -- if the observed staging differs from the expected the test fails. Signed-off-by:
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Janis Schoetterl-Glausch authored
In order to achieve good test coverage we need to be able to invoke the MEM_OP ioctl with all possible parametrizations. However, for a given test, we want to be concise and not specify a long list of default values for parameters not relevant for the test, so the readers attention is not needlessly diverted. Add a macro that enables this and convert the existing test to use it. The macro emulates named arguments and hides some of the ioctl's redundancy, e.g. sets the key flag if an access key is specified. Signed-off-by:
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Janis Schoetterl-Glausch authored
Split success case/copy test from error test, making them independent. This means they do not share state and are easier to understand. Also, new test can be added in the same manner without affecting the old ones. In order to make that simpler, introduce functionality for the setup of commonly used variables. Signed-off-by:
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Claudio Imbrenda authored
When handling the SCK instruction, the kvm lock is taken, even though the vcpu lock is already being held. The normal locking order is kvm lock first and then vcpu lock. This is can (and in some circumstances does) lead to deadlocks. The function kvm_s390_set_tod_clock is called both by the SCK handler and by some IOCTLs to set the clock. The IOCTLs will not hold the vcpu lock, so they can safely take the kvm lock. The SCK handler holds the vcpu lock, but will also somehow need to acquire the kvm lock without relinquishing the vcpu lock. The solution is to factor out the code to set the clock, and provide two wrappers. One is called like the original function and does the locking, the other is called kvm_s390_try_set_tod_clock and uses trylock to try to acquire the kvm lock. This new wrapper is then used in the SCK handler. If locking fails, -EAGAIN is returned, which is eventually propagated to userspace, thus also freeing the vcpu lock and allowing for forward progress. This is not the most efficient or elegant way to solve this issue, but the SCK instruction is deprecated and its performance is not critical. The goal of this patch is just to provide a simple but correct way to fix the bug. Fixes: 6a3f95a6 ("KVM: s390: Intercept SCK instruction") Signed-off-by:
Claudio Imbrenda <imbrenda@linux.ibm.com> Reviewed-by:
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- 11 Mar, 2022 9 commits
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Anup Patel authored
The SBI v0.3 specification extends SBI HSM extension by adding SBI HSM suspend call and related HART states. This patch extends the KVM RISC-V HSM implementation to provide KVM guest a minimal SBI HSM suspend call which is equivalent to a WFI instruction. Signed-off-by:
Anup Patel <apatel@ventanamicro.com> Reviewed-by:
Atish Patra <atishp@rivosinc.com> Signed-off-by:
Anup Patel <anup@brainfault.org>
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Anup Patel authored
The wait for interrupt (WFI) instruction emulation can share the VCPU halt logic with SBI HSM suspend emulation so this patch adds a common kvm_riscv_vcpu_wfi() function for this purpose. Signed-off-by:
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Anup Patel authored
We add defines related to SBI HSM suspend call and also update HSM states naming as-per the latest SBI specification. Signed-off-by:
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Anup Patel authored
The SBI v0.3 specification defines SRST (System Reset) extension which provides a standard poweroff and reboot interface. This patch implements SRST extension for the KVM Guest. Signed-off-by:
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Anup Patel authored
We rename kvm_sbi_system_shutdown() to kvm_riscv_vcpu_sbi_system_reset() and move it to vcpu_sbi.c so that it can be shared by SBI v0.1 shutdown and SBI v0.3 SRST extension. Signed-off-by:
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Anup Patel authored
We upgrade SBI spec version implemented by KVM RISC-V to v0.3 so that Guest kernel can probe and use SBI extensions added by the SBI v0.3 specification. Signed-off-by:
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Vincent Chen authored
Kernel uses __kvm_riscv_switch_to() and __kvm_switch_return() to switch the context of host kernel and guest kernel. Several CSRs belonging to the context will be read and written during the context switch. To ensure atomic read-modify-write control of CSR and ordering of CSR accesses, some hardware blocks flush the pipeline when writing a CSR. In this circumstance, grouping CSR executions together as much as possible can reduce the performance impact of the pipeline. Therefore, this commit reorders the CSR instructions to enhance the context switch performance.. Signed-off-by:
Vincent Chen <vincent.chen@sifive.com> Suggested-by:
Hsinyi Lee <hsinyi.lee@sifive.com> Suggested-by:
Fu-Ching Yang <fu-ching.yang@sifive.com> Signed-off-by:
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Guo Ren authored
Current riscv doesn't support the 32bit KVM API. Let's make it clear by not selecting KVM_COMPAT. Signed-off-by:
Guo Ren <guoren@linux.alibaba.com> Signed-off-by:
Guo Ren <guoren@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Anup Patel <anup@brainfault.org> Reviewed-by:
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Yang Li authored
Eliminate the following coccicheck warning: ./arch/riscv/kvm/vcpu_sbi_v01.c:117:2-3: Unneeded semicolon Reported-by:
Abaci Robot <abaci@linux.alibaba.com> Signed-off-by:
Yang Li <yang.lee@linux.alibaba.com> Signed-off-by:
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- 09 Mar, 2022 4 commits
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Marc Zyngier authored
* kvm-arm64/psci-1.1: : . : Limited PSCI-1.1 support from Will Deacon: : : This small series exposes the PSCI SYSTEM_RESET2 call to guests, which : allows the propagation of a "reset_type" and a "cookie" back to the VMM. : Although Linux guests only ever pass 0 for the type ("SYSTEM_WARM_RESET"), : the vendor-defined range can be used by a bootloader to provide additional : information about the reset, such as an error code. : . KVM: arm64: Really propagate PSCI SYSTEM_RESET2 arguments to userspace Signed-off-by: -
Will Deacon authored
Commit d43583b8 ("KVM: arm64: Expose PSCI SYSTEM_RESET2 call to the guest") hooked up the SYSTEM_RESET2 PSCI call for guests but failed to preserve its arguments for userspace, instead overwriting them with zeroes via smccc_set_retval(). As Linux only passes zeroes for these arguments, this appeared to be working for Linux guests. Oh well. Don't call smccc_set_retval() for a SYSTEM_RESET2 heading to userspace and instead set X0 (and only X0) explicitly to PSCI_RET_INTERNAL_FAILURE just in case the vCPU re-enters the guest. Fixes: d43583b8 ("KVM: arm64: Expose PSCI SYSTEM_RESET2 call to the guest") Reported-by:
Andrew Walbran <qwandor@google.com> Signed-off-by:
Will Deacon <will@kernel.org> Signed-off-by:
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Marc Zyngier authored
* kvm-arm64/misc-5.18: : . : Misc fixes for KVM/arm64 5.18: : : - Drop unused kvm parameter to kvm_psci_version() : : - Implement CONFIG_DEBUG_LIST at EL2 : : - Make CONFIG_ARM64_ERRATUM_2077057 default y : : - Only do the interrupt dance if we have exited because of an interrupt : : - Remove traces of 32bit ARM host support from the documentation : . Documentation: KVM: Update documentation to indicate KVM is arm64-only KVM: arm64: Only open the interrupt window on exit due to an interrupt KVM: arm64: Enable Cortex-A510 erratum 2077057 by default Signed-off-by: -
Oliver Upton authored
KVM support for 32-bit ARM hosts (KVM/arm) has been removed from the kernel since commit 541ad015 ("arm: Remove 32bit KVM host support"). There still exists some remnants of the old architecture in the KVM documentation. Remove all traces of 32-bit host support from the documentation. Note that AArch32 guests are still supported. Suggested-by:
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- 08 Mar, 2022 1 commit
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Suravee Suthikulpanit authored
Expand KVM's mask for the AVIC host physical ID to the full 12 bits defined by the architecture. The number of bits consumed by hardware is model specific, e.g. early CPUs ignored bits 11:8, but there is no way for KVM to enumerate the "true" size. So, KVM must allow using all bits, else it risks rejecting completely legal x2APIC IDs on newer CPUs. This means KVM relies on hardware to not assign x2APIC IDs that exceed the "true" width of the field, but presumably hardware is smart enough to tie the width to the max x2APIC ID. KVM also relies on hardware to support at least 8 bits, as the legacy xAPIC ID is writable by software. But, those assumptions are unavoidable due to the lack of any way to enumerate the "true" width. Cc: stable@vger.kernel.org Cc: Maxim Levitsky <mlevitsk@redhat.com> Suggested-by:
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Message-Id: <20220211000851.185799-1-suravee.suthikulpanit@amd.com> Signed-off-by:
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