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KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated

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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>
This commit is contained in:
James Morse 2022-03-18 17:48:40 +00:00 committed by Greg Kroah-Hartman
parent c20d551744
commit 5f051d32b0
3 changed files with 24 additions and 0 deletions
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7
arch/arm/include/asm/kvm_host.h
View File

@ -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__ */

5
arch/arm64/include/asm/kvm_host.h
View File

@ -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__ */

12
virt/kvm/arm/psci.c
View File

@ -429,6 +429,18 @@ int kvm_hvc_call_handler(struct kvm_vcpu *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: