arm64: KVM: Make VHE Stage-2 TLB invalidation operations non-interruptible

Contrary to the non-VHE version of the TLB invalidation helpers, the VHE
code  has interrupts enabled, meaning that we can take an interrupt in
the middle of such a sequence, and start running something else with
HCR_EL2.TGE cleared.

That's really not a good idea.

Take the heavy-handed option and disable interrupts in
__tlb_switch_to_guest_vhe, restoring them in __tlb_switch_to_host_vhe.
The latter also gain an ISB in order to make sure that TGE really has
taken effect.

Cc: stable@vger.kernel.org
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/tlb.c
index 4dbd9c69a96d097e56fb49a733ea55ea49219c97..7fcc9c1a5f45c2c4c73070113adcbc9adf449561 100644 (file)
--- a/arch/arm64/kvm/hyp/tlb.c
+++ b/arch/arm64/kvm/hyp/tlb.c
@@ -15,14 +15,19 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/irqflags.h>
+
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
 #include <asm/tlbflush.h>
 
-static void __hyp_text __tlb_switch_to_guest_vhe(struct kvm *kvm)
+static void __hyp_text __tlb_switch_to_guest_vhe(struct kvm *kvm,
+                                                unsigned long *flags)
 {
        u64 val;
 
+       local_irq_save(*flags);
+
        /*
         * With VHE enabled, we have HCR_EL2.{E2H,TGE} = {1,1}, and
         * most TLB operations target EL2/EL0. In order to affect the
@@ -37,7 +42,8 @@ static void __hyp_text __tlb_switch_to_guest_vhe(struct kvm *kvm)
        isb();
 }
 
-static void __hyp_text __tlb_switch_to_guest_nvhe(struct kvm *kvm)
+static void __hyp_text __tlb_switch_to_guest_nvhe(struct kvm *kvm,
+                                                 unsigned long *flags)
 {
        __load_guest_stage2(kvm);
        isb();
@@ -48,7 +54,8 @@ static hyp_alternate_select(__tlb_switch_to_guest,
                            __tlb_switch_to_guest_vhe,
                            ARM64_HAS_VIRT_HOST_EXTN);
 
-static void __hyp_text __tlb_switch_to_host_vhe(struct kvm *kvm)
+static void __hyp_text __tlb_switch_to_host_vhe(struct kvm *kvm,
+                                               unsigned long flags)
 {
        /*
         * We're done with the TLB operation, let's restore the host's
@@ -56,9 +63,12 @@ static void __hyp_text __tlb_switch_to_host_vhe(struct kvm *kvm)
         */
        write_sysreg(0, vttbr_el2);
        write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
+       isb();
+       local_irq_restore(flags);
 }
 
-static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm)
+static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm,
+                                                unsigned long flags)
 {
        write_sysreg(0, vttbr_el2);
 }
@@ -70,11 +80,13 @@ static hyp_alternate_select(__tlb_switch_to_host,
 
 void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
 {
+       unsigned long flags;
+
        dsb(ishst);
 
        /* Switch to requested VMID */
        kvm = kern_hyp_va(kvm);
-       __tlb_switch_to_guest()(kvm);
+       __tlb_switch_to_guest()(kvm, &flags);
 
        /*
         * We could do so much better if we had the VA as well.
@@ -117,36 +129,39 @@ void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
        if (!has_vhe() && icache_is_vpipt())
                __flush_icache_all();
 
-       __tlb_switch_to_host()(kvm);
+       __tlb_switch_to_host()(kvm, flags);
 }
 
 void __hyp_text __kvm_tlb_flush_vmid(struct kvm *kvm)
 {
+       unsigned long flags;
+
        dsb(ishst);
 
        /* Switch to requested VMID */
        kvm = kern_hyp_va(kvm);
-       __tlb_switch_to_guest()(kvm);
+       __tlb_switch_to_guest()(kvm, &flags);
 
        __tlbi(vmalls12e1is);
        dsb(ish);
        isb();
 
-       __tlb_switch_to_host()(kvm);
+       __tlb_switch_to_host()(kvm, flags);
 }
 
 void __hyp_text __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu)
 {
        struct kvm *kvm = kern_hyp_va(kern_hyp_va(vcpu)->kvm);
+       unsigned long flags;
 
        /* Switch to requested VMID */
-       __tlb_switch_to_guest()(kvm);
+       __tlb_switch_to_guest()(kvm, &flags);
 
        __tlbi(vmalle1);
        dsb(nsh);
        isb();
 
-       __tlb_switch_to_host()(kvm);
+       __tlb_switch_to_host()(kvm, flags);
 }
 
 void __hyp_text __kvm_flush_vm_context(void)