linux/arch
Sean Christopherson 0bc2732661 KVM: x86: WARN only once if KVM leaves a dangling userspace I/O request
Change a WARN_ON() to separate WARN_ON_ONCE() if KVM has an outstanding
PIO or MMIO request without an associated callback, i.e. if KVM queued a
userspace I/O exit but didn't actually exit to userspace before moving
on to something else.  Warning on every KVM_RUN risks spamming the kernel
if KVM gets into a bad state.  Opportunistically split the WARNs so that
it's easier to triage failures when a WARN fires.

Deliberately do not use KVM_BUG_ON(), i.e. don't kill the VM.  While the
WARN is all but guaranteed to fire if and only if there's a KVM bug, a
dangling I/O request does not present a danger to KVM (that flag is truly
truly consumed only in a single emulator path), and any such bug is
unlikely to be fatal to the VM (KVM essentially failed to do something it
shouldn't have tried to do in the first place).  In other words, note the
bug, but let the VM keep running.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20220711232750.1092012-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2022-07-13 18:14:06 -07:00
..
alpha Cleanups (and one fix) around struct mount handling. 2022-06-04 19:00:05 -07:00
arc This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
arm This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
arm64 KVM: Allow for different capacities in kvm_mmu_memory_cache structs 2022-06-24 04:52:00 -04:00
csky This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
hexagon fork: Generalize PF_IO_WORKER handling 2022-05-07 09:01:59 -05:00
ia64 Bitmap patches for 5.19-rc1 2022-06-04 14:04:27 -07:00
loongarch LoongArch: Add Loongson-3 default config file 2022-06-03 20:09:29 +08:00
m68k This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
microblaze This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
mips This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
nios2 This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
openrisc This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
parisc Kbuild updates for v5.19 (2nd) 2022-06-05 09:06:03 -07:00
powerpc This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
riscv KVM: Allow for different capacities in kvm_mmu_memory_cache structs 2022-06-24 04:52:00 -04:00
s390 KVM: Move kvm_arch_vcpu_precreate() under kvm->lock 2022-06-08 04:47:28 -04:00
sh This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
sparc This set of changes updates init and user mode helper tasks to be 2022-06-03 16:03:05 -07:00
um While looking at the ptrace problems with PREEMPT_RT and the problems 2022-06-03 16:13:25 -07:00
x86 KVM: x86: WARN only once if KVM leaves a dangling userspace I/O request 2022-07-13 18:14:06 -07:00
xtensa While looking at the ptrace problems with PREEMPT_RT and the problems 2022-06-03 16:13:25 -07:00
.gitignore
Kconfig A set of objtool fixes: 2022-06-05 09:45:27 -07:00