[patch V4 15/15] x86/kvm: Use generic exit to guest work function

Thomas Gleixner
2020-07-21T11:08:56Z

Use the generic infrastructure to check for and handle pending work before
entering into guest mode.

This now handles TIF_NOTIFY_RESUME as well which was ignored so
far. Handling it is important as this covers task work and task work will
be used to offload the heavy lifting of POSIX CPU timers to thread context.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kvm/Kconfig | 1 +
arch/x86/kvm/vmx/vmx.c | 11 +++++------
arch/x86/kvm/x86.c | 15 ++++++---------
3 files changed, 12 insertions(+), 15 deletions(-)

--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -42,6 +42,7 @@ config KVM
select HAVE_KVM_MSI
select HAVE_KVM_CPU_RELAX_INTERCEPT
select HAVE_KVM_NO_POLL
+ select KVM_EXIT_TO_GUEST_WORK
select KVM_GENERIC_DIRTYLOG_READ_PROTECT
select KVM_VFIO
select SRCU
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -27,6 +27,7 @@
#include <linux/slab.h>
#include <linux/tboot.h>
#include <linux/trace_events.h>
+#include <linux/entry-kvm.h>

#include <asm/apic.h>
#include <asm/asm.h>
@@ -5376,14 +5377,12 @@ static int handle_invalid_guest_state(st
}

/*
- * Note, return 1 and not 0, vcpu_run() is responsible for
- * morphing the pending signal into the proper return code.
+ * Note, return 1 and not 0, vcpu_run() will invoke
+ * exit_to_guest_mode() which will create a proper return
+ * code.
*/
- if (signal_pending(current))
+ if (__exit_to_guest_mode_work_pending())
return 1;
-
- if (need_resched())
- schedule();
}

return 1;
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -56,6 +56,7 @@
#include <linux/sched/stat.h>
#include <linux/sched/isolation.h>
#include <linux/mem_encrypt.h>
+#include <linux/entry-kvm.h>

#include <trace/events/kvm.h>

@@ -1585,7 +1586,7 @@ EXPORT_SYMBOL_GPL(kvm_emulate_wrmsr);
bool kvm_vcpu_exit_request(struct kvm_vcpu *vcpu)
{
return vcpu->mode == EXITING_GUEST_MODE || kvm_request_pending(vcpu) ||
- need_resched() || signal_pending(current);
+ exit_to_guest_mode_work_pending();
}
EXPORT_SYMBOL_GPL(kvm_vcpu_exit_request);

@@ -8676,15 +8677,11 @@ static int vcpu_run(struct kvm_vcpu *vcp
break;
}

- if (signal_pending(current)) {
- r = -EINTR;
- vcpu->run->exit_reason = KVM_EXIT_INTR;
- ++vcpu->stat.signal_exits;
- break;
- }
- if (need_resched()) {
+ if (exit_to_guest_mode_work_pending()) {
srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
- cond_resched();
+ r = exit_to_guest_mode(vcpu);
+ if (r)
+ return r;
vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
}
}