diff options
| author | Marc Zyngier <maz@kernel.org> | 2020-06-03 18:24:01 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-06-17 16:40:38 +0200 |
| commit | d96ef8fa953428fe5cf050bd3ed31ac11fb8bfe9 (patch) | |
| tree | 53a15e41f546a9db85b3d4e388305994f7477136 /arch/arm64/kvm | |
| parent | 812857678847423d44b18bdb68522f9c2e9c3dc9 (diff) | |
KVM: arm64: Save the host's PtrAuth keys in non-preemptible context
commit ef3e40a7ea8dbe2abd0a345032cd7d5023b9684f upstream.
When using the PtrAuth feature in a guest, we need to save the host's
keys before allowing the guest to program them. For that, we dump
them in a per-CPU data structure (the so called host context).
But both call sites that do this are in preemptible context,
which may end up in disaster should the vcpu thread get preempted
before reentering the guest.
Instead, save the keys eagerly on each vcpu_load(). This has an
increased overhead, but is at least safe.
Cc: stable@vger.kernel.org
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/handle_exit.c | 19 |
1 files changed, 2 insertions, 17 deletions
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 706cca23f0d2..1249f68a9418 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -162,31 +162,16 @@ static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run) return 1; } -#define __ptrauth_save_key(regs, key) \ -({ \ - regs[key ## KEYLO_EL1] = read_sysreg_s(SYS_ ## key ## KEYLO_EL1); \ - regs[key ## KEYHI_EL1] = read_sysreg_s(SYS_ ## key ## KEYHI_EL1); \ -}) - /* * Handle the guest trying to use a ptrauth instruction, or trying to access a * ptrauth register. */ void kvm_arm_vcpu_ptrauth_trap(struct kvm_vcpu *vcpu) { - struct kvm_cpu_context *ctxt; - - if (vcpu_has_ptrauth(vcpu)) { + if (vcpu_has_ptrauth(vcpu)) vcpu_ptrauth_enable(vcpu); - ctxt = vcpu->arch.host_cpu_context; - __ptrauth_save_key(ctxt->sys_regs, APIA); - __ptrauth_save_key(ctxt->sys_regs, APIB); - __ptrauth_save_key(ctxt->sys_regs, APDA); - __ptrauth_save_key(ctxt->sys_regs, APDB); - __ptrauth_save_key(ctxt->sys_regs, APGA); - } else { + else kvm_inject_undefined(vcpu); - } } /* |