Sean Christopherson 8646e53633 KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest ... Invoke rseq's NOTIFY_RESUME handler when processing the flag prior to transferring to a KVM guest, which is roughly equivalent to an exit to userspace and processes many of the same pending actions. While the task cannot be in an rseq critical section as the KVM path is reachable only by via ioctl(KVM_RUN), the side effects that apply to rseq outside of a critical section still apply, e.g. the current CPU needs to be updated if the task is migrated. Clearing TIF_NOTIFY_RESUME without informing rseq can lead to segfaults and other badness in userspace VMMs that use rseq in combination with KVM, e.g. due to the CPU ID being stale after task migration. Fixes: 72c3c0fe54 ("x86/kvm: Use generic xfer to guest work function") Reported-by: Peter Foley <pefoley@google.com> Bisected-by: Doug Evans <dje@google.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210901203030.1292304-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>		2021-09-22 10:24:01 -04:00
..
common.c	tick/nohz: Only check for RCU deferred wakeup on user/guest entry when needed	2021-05-31 10:14:49 +02:00
common.h	kernel: Implement selective syscall userspace redirection	2020-12-02 15:07:56 +01:00
kvm.c	KVM: rseq: Update rseq when processing NOTIFY_RESUME on xfer to KVM guest	2021-09-22 10:24:01 -04:00
Makefile	kernel: Implement selective syscall userspace redirection	2020-12-02 15:07:56 +01:00
syscall_user_dispatch.c	entry: Use different define for selector variable in SUD	2021-02-06 00:21:42 +01:00