[PATCH v2 3/5] KVM: nSVM: Move sync'ing to vmcb12 cache after completing interrupts

[Yosry Ahmed <yosry.ahmed@linux.dev>]

nested_sync_control_from_vmcb02() sync's some fields from vmcb02 to the
cached vmcb12 after a VMRUN of L2, mainly to keep the cache up-to-date
for save/restore. However, NextRIP is sync'd separately after
completing interrupts, as svm_complete_soft_interrupt() may update it
(e.g. for soft IRQ re-injection).

Move the call to nested_sync_control_from_vmcb02() after completing
interrupts, moving the NextRIP sync (and the FIXME) inside it. This
keeps the sync code together, and puts the FIXME in a more adequate
location, as it applies to most/all fields sync'd by
nested_sync_control_from_vmcb02().

Moving the call is safe, as nothing in-between accesses any of the VMCB
fields sync'd by nested_sync_control_from_vmcb02(), except NextRIP.

Opportunistically make some whitespace fixes. No functional change
intended.

Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
---
 arch/x86/kvm/svm/nested.c | 10 ++++++++--
 arch/x86/kvm/svm/svm.c    | 26 ++++++++++----------------
 2 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 9909ff237e5c..6a7c7c5b742a 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -519,9 +519,15 @@ void nested_copy_vmcb_save_to_cache(struct vcpu_svm *svm,
 void nested_sync_control_from_vmcb02(struct vcpu_svm *svm)
 {
 	u32 mask;
-	svm->nested.ctl.event_inj      = svm->vmcb->control.event_inj;
-	svm->nested.ctl.event_inj_err  = svm->vmcb->control.event_inj_err;
+
+	/*
+	 * FIXME: Rework svm_get_nested_state() to not pull data from the
+	 *        cache (except for maybe int_ctl).
+	 */
+	svm->nested.ctl.event_inj	= svm->vmcb->control.event_inj;
+	svm->nested.ctl.event_inj_err	= svm->vmcb->control.event_inj_err;
 	svm->nested.ctl.int_state	= svm->vmcb->control.int_state;
+	svm->nested.ctl.next_rip	= svm->vmcb->control.next_rip;
 
 	/* Only a few fields of int_ctl are written by the processor.  */
 	mask = V_IRQ_MASK | V_TPR_MASK;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 1073a32a96fa..458abead9d5b 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4399,17 +4399,6 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags)
 	sync_cr8_to_lapic(vcpu);
 
 	svm->next_rip = 0;
-	if (is_guest_mode(vcpu)) {
-		nested_sync_control_from_vmcb02(svm);
-
-		/* Track VMRUNs that have made past consistency checking */
-		if (svm->nested.nested_run_pending &&
-		    !svm_is_vmrun_failure(svm->vmcb->control.exit_code))
-                        ++vcpu->stat.nested_run;
-
-		svm->nested.nested_run_pending = 0;
-	}
-
 	svm->vmcb->control.tlb_ctl = TLB_CONTROL_DO_NOTHING;
 
 	/*
@@ -4438,12 +4427,17 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags)
 	/*
 	 * Update the cache after completing interrupts to get an accurate
 	 * NextRIP, e.g. when re-injecting a soft interrupt.
-	 *
-	 * FIXME: Rework svm_get_nested_state() to not pull data from the
-	 *        cache (except for maybe int_ctl).
 	 */
-	if (is_guest_mode(vcpu))
-		svm->nested.ctl.next_rip = svm->vmcb->control.next_rip;
+	if (is_guest_mode(vcpu)) {
+		nested_sync_control_from_vmcb02(svm);
+
+		/* Track VMRUNs that have made past consistency checking */
+		if (svm->nested.nested_run_pending &&
+		    !svm_is_vmrun_failure(svm->vmcb->control.exit_code))
+			++vcpu->stat.nested_run;
+
+		svm->nested.nested_run_pending = 0;
+	}
 
 	return svm_exit_handlers_fastpath(vcpu);
 }
-- 
2.53.0.239.g8d8fc8a987-goog