From: James Morse <james.morse@xxxxxxx>
commit a5905d6af492ee6a4a2205f0d550b3f931b03d03 upstream.
KVM allows the guest to discover whether the ARCH_WORKAROUND SMCCC are
implemented, and to preserve that state during migration through its
firmware register interface.
Add the necessary boiler plate for SMCCC_ARCH_WORKAROUND_3.
Reviewed-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
[ kvm code moved to virt/kvm/arm, removed fw regs ABI. Added 32bit stub ]
Signed-off-by: James Morse <james.morse@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/include/asm/kvm_host.h | 6 ++++++
arch/arm64/include/asm/kvm_host.h | 5 +++++
virt/kvm/arm/psci.c | 12 ++++++++++++
3 files changed, 23 insertions(+)
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -26,6 +26,7 @@
#include <asm/kvm_asm.h>
#include <asm/kvm_mmio.h>
#include <asm/fpstate.h>
+#include <asm/spectre.h>
#include <kvm/arm_arch_timer.h>
#define __KVM_HAVE_ARCH_INTC_INITIALIZED
@@ -324,4 +325,9 @@ static inline int kvm_arm_have_ssbd(void
return KVM_SSBD_UNKNOWN;
}
+static inline int kvm_arm_get_spectre_bhb_state(void)
+{
+ /* 32bit guests don't need firmware for this */
+ return SPECTRE_VULNERABLE; /* aka SMCCC_RET_NOT_SUPPORTED */
+}
#endif /* __ARM_KVM_HOST_H__ */
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -450,4 +450,9 @@ static inline int kvm_arm_have_ssbd(void
}
}
+static inline enum mitigation_state kvm_arm_get_spectre_bhb_state(void)
+{
+ return arm64_get_spectre_bhb_state();
+}
+
#endif /* __ARM64_KVM_HOST_H__ */
--- a/virt/kvm/arm/psci.c
+++ b/virt/kvm/arm/psci.c
@@ -433,6 +433,18 @@ int kvm_hvc_call_handler(struct kvm_vcpu
break;
}
break;
+ case ARM_SMCCC_ARCH_WORKAROUND_3:
+ switch (kvm_arm_get_spectre_bhb_state()) {
+ case SPECTRE_VULNERABLE:
+ break;
+ case SPECTRE_MITIGATED:
+ val = SMCCC_RET_SUCCESS;
+ break;
+ case SPECTRE_UNAFFECTED:
+ val = SMCCC_ARCH_WORKAROUND_RET_UNAFFECTED;
+ break;
+ }
+ break;
}
break;
default:
