[PATCH 1/2] KVM: SVM: don't check have_run_cpus in sev_writeback_caches()

[Yury Norov]

From: Yury Norov (NVIDIA) <yury.norov@xxxxxxxxx>

Before calling wbnoinvd_on_cpus_mask(), the function checks the cpumask
for emptiness. It's useless, as the following wbnoinvd_on_cpus_mask()
ends up with smp_call_function_many_cond(), which handles empty cpumask
correctly.

While there, move function-wide comment on top of the function.

Fixes: 6f38f8c57464 ("KVM: SVM: Flush cache only on CPUs running SEV guest")
Signed-off-by: Yury Norov (NVIDIA) <yury.norov@xxxxxxxxx>
---
 arch/x86/kvm/svm/sev.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 2fbdebf79fbb..49d7557de8bc 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -716,15 +716,12 @@ static void sev_clflush_pages(struct page *pages[], unsigned long npages)
 	}
 }
 
+/*
+ * The caller is responsible for ensuring correctness if the mask
+ * can be modified, e.g. if a CPU could be doing VMRUN.
+ */
 static void sev_writeback_caches(struct kvm *kvm)
 {
-	/*
-	 * Note, the caller is responsible for ensuring correctness if the mask
-	 * can be modified, e.g. if a CPU could be doing VMRUN.
-	 */
-	if (cpumask_empty(to_kvm_sev_info(kvm)->have_run_cpus))
-		return;
-
 	/*
 	 * Ensure that all dirty guest tagged cache entries are written back
 	 * before releasing the pages back to the system for use.  CLFLUSH will
-- 
2.43.0