linux-kernel - [RFC PATCH 12/18] KVM: Do processor compatibility check on cpu online and resume

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Date:   Fri, 19 Aug 2022 23:00:18 -0700
From:   isaku.yamahata@...el.com
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Kai Huang <kai.huang@...el.com>, Chao Gao <chao.gao@...el.com>,
        Will Deacon <will@...nel.org>
Subject: [RFC PATCH 12/18] KVM: Do processor compatibility check on cpu online and resume

From: Isaku Yamahata <isaku.yamahata@...el.com>

So far the processor compatibility check is not done for newly added CPU.
It should be done.

Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
---
 virt/kvm/kvm_arch.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/virt/kvm/kvm_arch.c b/virt/kvm/kvm_arch.c
index 2ed8de0591c9..20971f43df95 100644
--- a/virt/kvm/kvm_arch.c
+++ b/virt/kvm/kvm_arch.c
@@ -99,9 +99,15 @@ __weak int kvm_arch_del_vm(int usage_count)
 
 __weak int kvm_arch_online_cpu(unsigned int cpu, int usage_count)
 {
-	if (usage_count)
-		return __hardware_enable();
-	return 0;
+	int r;
+
+	if (!usage_count)
+		return 0;
+
+	r = kvm_arch_check_processor_compat();
+	if (r)
+		return r;
+	return __hardware_enable();
 }
 
 __weak int kvm_arch_offline_cpu(unsigned int cpu, int usage_count)
@@ -126,6 +132,10 @@ __weak int kvm_arch_suspend(int usage_count)
 
 __weak void kvm_arch_resume(int usage_count)
 {
-	if (usage_count)
-		(void)__hardware_enable();
+	if (!usage_count)
+		return;
+
+	if (kvm_arch_check_processor_compat())
+		return; /* FIXME: disable KVM */
+	(void)__hardware_enable();
 }
-- 
2.25.1