From: James Morse james.morse@arm.com
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@armlinux.org.uk Reviewed-by: Catalin Marinas catalin.marinas@arm.com [ kvm code moved to arch/arm/kvm, removed fw regs ABI. Added 32bit stub ] Signed-off-by: James Morse james.morse@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm/include/asm/kvm_host.h | 5 +++++ arch/arm/kvm/psci.c | 4 ++++ arch/arm64/include/asm/kvm_host.h | 4 ++++ 3 files changed, 13 insertions(+)
--- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -349,4 +349,9 @@ static inline int kvm_arm_have_ssbd(void return KVM_SSBD_UNKNOWN; }
+static inline bool kvm_arm_spectre_bhb_mitigated(void) +{ + /* 32bit guests don't need firmware for this */ + return false; +} #endif /* __ARM_KVM_HOST_H__ */ --- a/arch/arm/kvm/psci.c +++ b/arch/arm/kvm/psci.c @@ -431,6 +431,10 @@ int kvm_hvc_call_handler(struct kvm_vcpu break; } break; + case ARM_SMCCC_ARCH_WORKAROUND_3: + if (kvm_arm_spectre_bhb_mitigated()) + val = SMCCC_RET_SUCCESS; + break; } break; default: --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -452,4 +452,8 @@ static inline int kvm_arm_have_ssbd(void } }
+static inline bool kvm_arm_spectre_bhb_mitigated(void) +{ + return arm64_get_spectre_bhb_state() == SPECTRE_MITIGATED; +} #endif /* __ARM64_KVM_HOST_H__ */