commit 2a3f93459d689d990b3ecfbe782fec89b97d3279 upstream.

Not all execution modes are valid for a guest, and some of them depend on what the HW actually supports. Let's verify that what userspace provides is compatible with both the VM settings and the HW capabilities.

Cc: stable@vger.kernel.org Fixes: 0d854a60b1d7 ("arm64: KVM: enable initialization of a 32bit vcpu") Reviewed-by: Christoffer Dall christoffer.dall@arm.com Reviewed-by: Mark Rutland mark.rutland@arm.com Reviewed-by: Dave Martin Dave.Martin@arm.com Signed-off-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Marc Zyngier marc.zyngier@arm.com --- arch/arm64/kvm/guest.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 4a177629862b..d5c6bb1562d8 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -152,17 +152,25 @@ static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) }

if (off == KVM_REG_ARM_CORE_REG(regs.pstate)) { - u32 mode = (*(u32 *)valp) & COMPAT_PSR_MODE_MASK; + u64 mode = (*(u64 *)valp) & COMPAT_PSR_MODE_MASK; switch (mode) { case COMPAT_PSR_MODE_USR: + if (!system_supports_32bit_el0()) + return -EINVAL; + break; case COMPAT_PSR_MODE_FIQ: case COMPAT_PSR_MODE_IRQ: case COMPAT_PSR_MODE_SVC: case COMPAT_PSR_MODE_ABT: case COMPAT_PSR_MODE_UND: + if (!vcpu_el1_is_32bit(vcpu)) + return -EINVAL; + break; case PSR_MODE_EL0t: case PSR_MODE_EL1t: case PSR_MODE_EL1h: + if (vcpu_el1_is_32bit(vcpu)) + return -EINVAL; break; default: err = -EINVAL;