| From foo@baz Sat Mar 19 01:51:18 PM CET 2022 |
| From: James Morse <james.morse@arm.com> |
| Date: Fri, 18 Mar 2022 17:48:40 +0000 |
| Subject: KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated |
| To: stable@vger.kernel.org |
| Cc: linux-kernel@vger.kernel.org, james.morse@arm.com, catalin.marinas@arm.com |
| Message-ID: <20220318174842.2321061-21-james.morse@arm.com> |
| |
| 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 virt/kvm/arm, 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 | 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: |