diff options
| author | Marc Zyngier <marc.zyngier@arm.com> | 2018-07-20 10:53:10 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-07-22 14:28:51 +0200 |
| commit | 805357aa65bbc419451fb9556968687c7fd1d2e1 (patch) | |
| tree | 635d37928233b9f5928c4d6b5bc816abfe2be9cb /arch/arm64/kvm/hyp/switch.c | |
| parent | 0592871918f0acf369cec5c88de1fa76dbf2c1a2 (diff) | |
arm64: KVM: Add ARCH_WORKAROUND_2 support for guests
commit 55e3748e8902ff641e334226bdcb432f9a5d78d3 upstream.
In order to offer ARCH_WORKAROUND_2 support to guests, we need
a bit of infrastructure.
Let's add a flag indicating whether or not the guest uses
SSBD mitigation. Depending on the state of this flag, allow
KVM to disable ARCH_WORKAROUND_2 before entering the guest,
and enable it when exiting it.
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm64/kvm/hyp/switch.c')
| -rw-r--r-- | arch/arm64/kvm/hyp/switch.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 1f41b0fe59bc..b2f1992c6234 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -15,6 +15,7 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <linux/arm-smccc.h> #include <linux/types.h> #include <linux/jump_label.h> #include <uapi/linux/psci.h> @@ -281,6 +282,39 @@ static void __hyp_text __skip_instr(struct kvm_vcpu *vcpu) write_sysreg_el2(*vcpu_pc(vcpu), elr); } +static inline bool __hyp_text __needs_ssbd_off(struct kvm_vcpu *vcpu) +{ + if (!cpus_have_const_cap(ARM64_SSBD)) + return false; + + return !(vcpu->arch.workaround_flags & VCPU_WORKAROUND_2_FLAG); +} + +static void __hyp_text __set_guest_arch_workaround_state(struct kvm_vcpu *vcpu) +{ +#ifdef CONFIG_ARM64_SSBD + /* + * The host runs with the workaround always present. If the + * guest wants it disabled, so be it... + */ + if (__needs_ssbd_off(vcpu) && + __hyp_this_cpu_read(arm64_ssbd_callback_required)) + arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, 0, NULL); +#endif +} + +static void __hyp_text __set_host_arch_workaround_state(struct kvm_vcpu *vcpu) +{ +#ifdef CONFIG_ARM64_SSBD + /* + * If the guest has disabled the workaround, bring it back on. + */ + if (__needs_ssbd_off(vcpu) && + __hyp_this_cpu_read(arm64_ssbd_callback_required)) + arm_smccc_1_1_smc(ARM_SMCCC_ARCH_WORKAROUND_2, 1, NULL); +#endif +} + int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu) { struct kvm_cpu_context *host_ctxt; @@ -311,6 +345,8 @@ int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu) __sysreg_restore_guest_state(guest_ctxt); __debug_restore_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt); + __set_guest_arch_workaround_state(vcpu); + /* Jump in the fire! */ again: exit_code = __guest_enter(vcpu, host_ctxt); @@ -367,6 +403,8 @@ again: /* 0 falls through to be handled out of EL2 */ } + __set_host_arch_workaround_state(vcpu); + if (cpus_have_const_cap(ARM64_HARDEN_BP_POST_GUEST_EXIT)) { u32 midr = read_cpuid_id(); |