[PATCH v3 08/16] KVM: arm64: nv: Handle TLBI VMALLS12E1{,IS} operations

Marc Zyngier
2024-06-14T14:46:17Z

Emulating TLBI VMALLS12E1* results in tearing down all the shadow
S2 PTs that match the current VMID, since our shadow S2s are just
some form of SW-managed TLBs. That teardown itself results in a
full TLB invalidation for both S1 and S2.

This can result in over-invalidation if two vcpus use the same VMID
to tag private S2 PTs, but this is still correct from an architecture
perspective.

Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
arch/arm64/kvm/sys_regs.c | 51 +++++++++++++++++++++++++++++++++++++++
1 file changed, 51 insertions(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index b22309fca3a7..22a3691ce248 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2741,6 +2741,22 @@ static const struct sys_reg_desc sys_reg_descs[] = {
EL2_REG(SP_EL2, NULL, reset_unknown, 0),
};

+static bool kvm_supported_tlbi_s12_op(struct kvm_vcpu *vpcu, u32 instr)
+{
+ struct kvm *kvm = vpcu->kvm;
+ u8 CRm = sys_reg_CRm(instr);
+
+ if (sys_reg_CRn(instr) == TLBI_CRn_nXS &&
+ !kvm_has_feat(kvm, ID_AA64ISAR1_EL1, XS, IMP))
+ return false;
+
+ if (CRm == TLBI_CRm_nROS &&
+ !kvm_has_feat(kvm, ID_AA64ISAR0_EL1, TLB, OS))
+ return false;
+
+ return true;
+}
+
/* Only defined here as this is an internal "abstraction" */
union tlbi_info {
struct {
@@ -2758,6 +2774,38 @@ union tlbi_info {
} va;
};

+static void s2_mmu_unmap_range(struct kvm_s2_mmu *mmu,
+ const union tlbi_info *info)
+{
+ kvm_stage2_unmap_range(mmu, info->range.start, info->range.size);
+}
+
+static bool handle_vmalls12e1is(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
+ const struct sys_reg_desc *r)
+{
+ u32 sys_encoding = sys_insn(p->Op0, p->Op1, p->CRn, p->CRm, p->Op2);
+ u64 limit, vttbr;
+
+ if (!kvm_supported_tlbi_s12_op(vcpu, sys_encoding)) {
+ kvm_inject_undefined(vcpu);
+ return false;
+ }
+
+ vttbr = vcpu_read_sys_reg(vcpu, VTTBR_EL2);
+ limit = BIT_ULL(kvm_get_pa_bits(vcpu->kvm));
+
+ kvm_s2_mmu_iterate_by_vmid(vcpu->kvm, get_vmid(vttbr),
+ &(union tlbi_info) {
+ .range = {
+ .start = 0,
+ .size = limit,
+ },
+ },
+ s2_mmu_unmap_range);
+
+ return true;
+}
+
static void s2_mmu_tlbi_s1e1(struct kvm_s2_mmu *mmu,
const union tlbi_info *info)
{
@@ -2831,6 +2879,9 @@ static struct sys_reg_desc sys_insn_descs[] = {
SYS_INSN(TLBI_VAAE1, handle_tlbi_el1),
SYS_INSN(TLBI_VALE1, handle_tlbi_el1),
SYS_INSN(TLBI_VAALE1, handle_tlbi_el1),
+
+ SYS_INSN(TLBI_VMALLS12E1IS, handle_vmalls12e1is),
+ SYS_INSN(TLBI_VMALLS12E1, handle_vmalls12e1is),
};

static const struct sys_reg_desc *first_idreg;
--
2.39.2