diff options
| author | Sean Christopherson <seanjc@google.com> | 2021-08-10 07:45:26 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-15 09:47:41 +0200 |
| commit | 06dad664d4eae136e8dfa9eea955b154213f3f2e (patch) | |
| tree | eac8649ca53e298e0d7167dc67386a3798d89b5f /arch/x86 | |
| parent | 1735cec1e83c5e1b93de47c07d74d706644394ad (diff) | |
KVM: nVMX: Unconditionally clear nested.pi_pending on nested VM-Enter
commit f7782bb8d818d8f47c26b22079db10599922787a upstream.
Clear nested.pi_pending on nested VM-Enter even if L2 will run without
posted interrupts enabled. If nested.pi_pending is left set from a
previous L2, vmx_complete_nested_posted_interrupt() will pick up the
stale flag and exit to userspace with an "internal emulation error" due
the new L2 not having a valid nested.pi_desc.
Arguably, vmx_complete_nested_posted_interrupt() should first check for
posted interrupts being enabled, but it's also completely reasonable that
KVM wouldn't screw up a fundamental flag. Not to mention that the mere
existence of nested.pi_pending is a long-standing bug as KVM shouldn't
move the posted interrupt out of the IRR until it's actually processed,
e.g. KVM effectively drops an interrupt when it performs a nested VM-Exit
with a "pending" posted interrupt. Fixing the mess is a future problem.
Prior to vmx_complete_nested_posted_interrupt() interpreting a null PI
descriptor as an error, this was a benign bug as the null PI descriptor
effectively served as a check on PI not being enabled. Even then, the
new flow did not become problematic until KVM started checking the result
of kvm_check_nested_events().
Fixes: 705699a13994 ("KVM: nVMX: Enable nested posted interrupt processing")
Fixes: 966eefb89657 ("KVM: nVMX: Disable vmcs02 posted interrupts if vmcs12 PID isn't mappable")
Fixes: 47d3530f86c0 ("KVM: x86: Exit to userspace when kvm_check_nested_events fails")
Cc: stable@vger.kernel.org
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210810144526.2662272-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/vmx/nested.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 023bd3e1aa0d..3041015b05f7 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2057,12 +2057,11 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12) ~PIN_BASED_VMX_PREEMPTION_TIMER); /* Posted interrupts setting is only taken from vmcs12. */ - if (nested_cpu_has_posted_intr(vmcs12)) { + vmx->nested.pi_pending = false; + if (nested_cpu_has_posted_intr(vmcs12)) vmx->nested.posted_intr_nv = vmcs12->posted_intr_nv; - vmx->nested.pi_pending = false; - } else { + else exec_control &= ~PIN_BASED_POSTED_INTR; - } pin_controls_set(vmx, exec_control); /* |