arm64: KVM: VHE: Clear HCR_TGE when invalidating guest TLBs

BugLink: http://bugs.launchpad.net/bugs/1675032
commit 68925176296a8b995e503349200e256674bfe5ac upstream.

When invalidating guest TLBs, special care must be taken to
actually shoot the guest TLBs and not the host ones if we're
running on a VHE system.  This is controlled by the HCR_EL2.TGE
bit, which we forget to clear before invalidating TLBs.

Address the issue by introducing two wrappers (__tlb_switch_to_guest
and __tlb_switch_to_host) that take care of both the VTTBR_EL2
and HCR_EL2.TGE switching.

Reported-by: Tomasz Nowicki <tnowicki@caviumnetworks.com>
Tested-by: Tomasz Nowicki <tnowicki@caviumnetworks.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/tlb.c
index e8e7ba2bc11f93abde92c6b91782ae776bdbcb73..9e1d2b75eecd606df6a6ccf632247ebc02149c67 100644 (file)
--- a/arch/arm64/kvm/hyp/tlb.c
+++ b/arch/arm64/kvm/hyp/tlb.c
@@ -18,14 +18,62 @@
 #include <asm/kvm_hyp.h>
 #include <asm/tlbflush.h>
 
+static void __hyp_text __tlb_switch_to_guest_vhe(struct kvm *kvm)
+{
+       u64 val;
+
+       /*
+        * With VHE enabled, we have HCR_EL2.{E2H,TGE} = {1,1}, and
+        * most TLB operations target EL2/EL0. In order to affect the
+        * guest TLBs (EL1/EL0), we need to change one of these two
+        * bits. Changing E2H is impossible (goodbye TTBR1_EL2), so
+        * let's flip TGE before executing the TLB operation.
+        */
+       write_sysreg(kvm->arch.vttbr, vttbr_el2);
+       val = read_sysreg(hcr_el2);
+       val &= ~HCR_TGE;
+       write_sysreg(val, hcr_el2);
+       isb();
+}
+
+static void __hyp_text __tlb_switch_to_guest_nvhe(struct kvm *kvm)
+{
+       write_sysreg(kvm->arch.vttbr, vttbr_el2);
+       isb();
+}
+
+static hyp_alternate_select(__tlb_switch_to_guest,
+                           __tlb_switch_to_guest_nvhe,
+                           __tlb_switch_to_guest_vhe,
+                           ARM64_HAS_VIRT_HOST_EXTN);
+
+static void __hyp_text __tlb_switch_to_host_vhe(struct kvm *kvm)
+{
+       /*
+        * We're done with the TLB operation, let's restore the host's
+        * view of HCR_EL2.
+        */
+       write_sysreg(0, vttbr_el2);
+       write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
+}
+
+static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm)
+{
+       write_sysreg(0, vttbr_el2);
+}
+
+static hyp_alternate_select(__tlb_switch_to_host,
+                           __tlb_switch_to_host_nvhe,
+                           __tlb_switch_to_host_vhe,
+                           ARM64_HAS_VIRT_HOST_EXTN);
+
 void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
 {
        dsb(ishst);
 
        /* Switch to requested VMID */
        kvm = kern_hyp_va(kvm);
-       write_sysreg(kvm->arch.vttbr, vttbr_el2);
-       isb();
+       __tlb_switch_to_guest()(kvm);
 
        /*
         * We could do so much better if we had the VA as well.
@@ -46,7 +94,7 @@ void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
        dsb(ish);
        isb();
 
-       write_sysreg(0, vttbr_el2);
+       __tlb_switch_to_host()(kvm);
 }
 
 void __hyp_text __kvm_tlb_flush_vmid(struct kvm *kvm)
@@ -55,14 +103,13 @@ void __hyp_text __kvm_tlb_flush_vmid(struct kvm *kvm)
 
        /* Switch to requested VMID */
        kvm = kern_hyp_va(kvm);
-       write_sysreg(kvm->arch.vttbr, vttbr_el2);
-       isb();
+       __tlb_switch_to_guest()(kvm);
 
        __tlbi(vmalls12e1is);
        dsb(ish);
        isb();
 
-       write_sysreg(0, vttbr_el2);
+       __tlb_switch_to_host()(kvm);
 }
 
 void __hyp_text __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu)
@@ -70,14 +117,13 @@ void __hyp_text __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu)
        struct kvm *kvm = kern_hyp_va(kern_hyp_va(vcpu)->kvm);
 
        /* Switch to requested VMID */
-       write_sysreg(kvm->arch.vttbr, vttbr_el2);
-       isb();
+       __tlb_switch_to_guest()(kvm);
 
        __tlbi(vmalle1);
        dsb(nsh);
        isb();
 
-       write_sysreg(0, vttbr_el2);
+       __tlb_switch_to_host()(kvm);
 }
 
 void __hyp_text __kvm_flush_vm_context(void)