linux-kernel - [PATCH] KVM: x86: support CONFIG_KVM_AMD=y with CONFIG_CRYPTO_DEV_CCP

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Message-Id: <1539103166-16317-1-git-send-email-pbonzini@redhat.com>
Date:   Tue,  9 Oct 2018 18:39:26 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: [PATCH] KVM: x86: support CONFIG_KVM_AMD=y with CONFIG_CRYPTO_DEV_CCP_DD=m

SEV requires access to the AMD cryptographic device APIs, and this
does not work when KVM is builtin and the crypto driver is a module.
Actually the Kconfig conditions for CONFIG_KVM_AMD_SEV try to disable
SEV in that case, but it does not work because the actual crypto
calls are not culled, only sev_hardware_setup() is.

This patch adds two CONFIG_KVM_AMD_SEV checks that gate all the remaining
SEV code; it fixes this particular configuration, and drops 5 KiB of
code when CONFIG_KVM_AMD_SEV=n.

Reported-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/svm.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index d96092b35936..61ccfb13899e 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -436,14 +436,18 @@ static inline struct kvm_svm *to_kvm_svm(struct kvm *kvm)

 static inline bool svm_sev_enabled(void)
 {
-	return max_sev_asid;
+	return IS_ENABLED(CONFIG_KVM_AMD_SEV) ? max_sev_asid : 0;
 }

 static inline bool sev_guest(struct kvm *kvm)
 {
+#ifdef CONFIG_KVM_AMD_SEV
 	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;

 	return sev->active;
+#else
+	return false;
+#endif
 }

 static inline int sev_get_asid(struct kvm *kvm)
-- 
1.8.3.1