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 | 7 +++++++
arch/arm64/include/asm/kvm_host.h | 5 +++++
virt/kvm/arm/psci.c | 12 ++++++++++++
3 files changed, 24 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
@@ -367,4 +368,10 @@ void kvm_arch_free_vm(struct kvm *kvm);
#define kvm_arm_vcpu_loaded(vcpu) (false)
+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
@@ -542,4 +542,9 @@ void kvm_arch_free_vm(struct kvm *kvm);
#define kvm_arm_vcpu_loaded(vcpu) ((vcpu)->arch.sysregs_loaded_on_cpu)
+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
@@ -429,6 +429,18 @@ 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:
Patches currently in stable-queue which might be from james.morse@xxxxxxx are
queue-4.19/arm64-entry-add-macro-for-reading-symbol-addresses-from-the-trampoline.patch
queue-4.19/arm64-use-the-clearbhb-instruction-in-mitigations.patch
queue-4.19/arm64-add-percpu-vectors-for-el1.patch
queue-4.19/arm64-entry-free-up-another-register-on-kpti-s-tramp_exit-path.patch
queue-4.19/arm64-entry-don-t-assume-tramp_vectors-is-the-start-of-the-vectors.patch
queue-4.19/arm64-entry-make-the-trampoline-cleanup-optional.patch
queue-4.19/kvm-arm64-add-templates-for-bhb-mitigation-sequences.patch
queue-4.19/arm64-entry-add-non-kpti-__bp_harden_el1_vectors-for-mitigations.patch
queue-4.19/arm64-add-id_aa64isar2_el1-sys-register.patch
queue-4.19/kvm-arm64-allow-smccc_arch_workaround_3-to-be-discovered-and-migrated.patch
queue-4.19/arm64-add-neoverse-n2-cortex-a710-cpu-part-definition.patch
queue-4.19/arm64-entry-move-trampoline-macros-out-of-ifdef-d-section.patch
queue-4.19/arm64-entry-allow-tramp_alias-to-access-symbols-after-the-4k-boundary.patch
queue-4.19/arm64-add-part-number-for-arm-cortex-a77.patch
queue-4.19/arm64-entry-move-the-trampoline-data-page-before-the-text-page.patch
queue-4.19/arm64-entry.s-add-ventry-overflow-sanity-checks.patch
queue-4.19/arm64-entry-add-vectors-that-have-the-bhb-mitigation-sequences.patch
queue-4.19/arm64-mitigate-spectre-style-branch-history-side-channels.patch
queue-4.19/arm64-entry-allow-the-trampoline-text-to-occupy-multiple-pages.patch
queue-4.19/arm64-proton-pack-report-spectre-bhb-vulnerabilities-as-part-of-spectre-v2.patch
queue-4.19/arm64-add-cortex-x2-cpu-part-definition.patch
queue-4.19/arm64-entry-make-the-kpti-trampoline-s-kpti-sequence-optional.patch
