leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

arm64: KVM: Propagate full Spectre v2 workaround state to KVM guests

Browse Source 
Recent commits added the explicit notion of "workaround not required" to
the state of the Spectre v2 (aka. BP_HARDENING) workaround, where we
just had "needed" and "unknown" before.

Export this knowledge to the rest of the kernel and enhance the existing
kvm_arm_harden_branch_predictor() to report this new state as well.
Export this new state to guests when they use KVM's firmware interface
emulation.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Andre Przywara
2019-05-03 15:27:48 +01:00
committed by Marc Zyngier
parent 80f393a23b
commit c118bbb527
5 changed files with 56 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
arch/arm64/include/asm/cpufeature.h
View File

@@ -614,6 +614,12 @@ static inline bool system_uses_irq_prio_masking(void)
cpus_have_const_cap(ARM64_HAS_IRQ_PRIO_MASKING);
}
#define ARM64_BP_HARDEN_UNKNOWN -1
#define ARM64_BP_HARDEN_WA_NEEDED 0
#define ARM64_BP_HARDEN_NOT_REQUIRED 1
int get_spectre_v2_workaround_state(void);
#define ARM64_SSBD_UNKNOWN -1
#define ARM64_SSBD_FORCE_DISABLE 0
#define ARM64_SSBD_KERNEL 1

16
arch/arm64/include/asm/kvm_host.h
View File

@@ -620,9 +620,21 @@ static inline void kvm_arm_vhe_guest_exit(void)
isb();
}
static inline bool kvm_arm_harden_branch_predictor(void)
#define KVM_BP_HARDEN_UNKNOWN -1
#define KVM_BP_HARDEN_WA_NEEDED 0
#define KVM_BP_HARDEN_NOT_REQUIRED 1
static inline int kvm_arm_harden_branch_predictor(void)
{
return cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR);
switch (get_spectre_v2_workaround_state()) {
case ARM64_BP_HARDEN_WA_NEEDED:
return KVM_BP_HARDEN_WA_NEEDED;
case ARM64_BP_HARDEN_NOT_REQUIRED:
return KVM_BP_HARDEN_NOT_REQUIRED;
case ARM64_BP_HARDEN_UNKNOWN:
default:
return KVM_BP_HARDEN_UNKNOWN;
}
}
#define KVM_SSBD_UNKNOWN -1