KVM: arm64: nv: Add trap forwarding for CNTHCTL_EL2

Describe the CNTHCTL_EL2 register, and associate it with all the sysregs
it allows to trap.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Jing Zhang <jingzhangos@google.com>
Link: https://lore.kernel.org/r/20230815183903.2735724-19-maz@kernel.org

diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index 241e44eeed6d6b6698384a310dce32ff4df0b24f..860910386b5b5e3f81aa54b2bff2d10f6c885c72 100644 (file)
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -100,9 +100,11 @@ enum cgt_group_id {
 
        /*
         * Anything after this point requires a callback evaluating a
-        * complex trap condition. Hopefully we'll never need this...
+        * complex trap condition. Ugly stuff.
         */
        __COMPLEX_CONDITIONS__,
+       CGT_CNTHCTL_EL1PCTEN = __COMPLEX_CONDITIONS__,
+       CGT_CNTHCTL_EL1PTEN,
 
        /* Must be last */
        __NR_CGT_GROUP_IDS__
@@ -369,10 +371,51 @@ static const enum cgt_group_id *coarse_control_combo[] = {
 
 typedef enum trap_behaviour (*complex_condition_check)(struct kvm_vcpu *);
 
+/*
+ * Warning, maximum confusion ahead.
+ *
+ * When E2H=0, CNTHCTL_EL2[1:0] are defined as EL1PCEN:EL1PCTEN
+ * When E2H=1, CNTHCTL_EL2[11:10] are defined as EL1PTEN:EL1PCTEN
+ *
+ * Note the single letter difference? Yet, the bits have the same
+ * function despite a different layout and a different name.
+ *
+ * We don't try to reconcile this mess. We just use the E2H=0 bits
+ * to generate something that is in the E2H=1 format, and live with
+ * it. You're welcome.
+ */
+static u64 get_sanitized_cnthctl(struct kvm_vcpu *vcpu)
+{
+       u64 val = __vcpu_sys_reg(vcpu, CNTHCTL_EL2);
+
+       if (!vcpu_el2_e2h_is_set(vcpu))
+               val = (val & (CNTHCTL_EL1PCEN | CNTHCTL_EL1PCTEN)) << 10;
+
+       return val & ((CNTHCTL_EL1PCEN | CNTHCTL_EL1PCTEN) << 10);
+}
+
+static enum trap_behaviour check_cnthctl_el1pcten(struct kvm_vcpu *vcpu)
+{
+       if (get_sanitized_cnthctl(vcpu) & (CNTHCTL_EL1PCTEN << 10))
+               return BEHAVE_HANDLE_LOCALLY;
+
+       return BEHAVE_FORWARD_ANY;
+}
+
+static enum trap_behaviour check_cnthctl_el1pten(struct kvm_vcpu *vcpu)
+{
+       if (get_sanitized_cnthctl(vcpu) & (CNTHCTL_EL1PCEN << 10))
+               return BEHAVE_HANDLE_LOCALLY;
+
+       return BEHAVE_FORWARD_ANY;
+}
+
 #define CCC(id, fn)                            \
        [id - __COMPLEX_CONDITIONS__] = fn
 
 static const complex_condition_check ccc[] = {
+       CCC(CGT_CNTHCTL_EL1PCTEN, check_cnthctl_el1pcten),
+       CCC(CGT_CNTHCTL_EL1PTEN, check_cnthctl_el1pten),
 };
 
 /*
@@ -877,6 +920,11 @@ static const struct encoding_to_trap_config encoding_to_cgt[] __initconst = {
        SR_TRAP(SYS_TRBPTR_EL1,         CGT_MDCR_E2TB),
        SR_TRAP(SYS_TRBSR_EL1,          CGT_MDCR_E2TB),
        SR_TRAP(SYS_TRBTRG_EL1,         CGT_MDCR_E2TB),
+       SR_TRAP(SYS_CNTP_TVAL_EL0,      CGT_CNTHCTL_EL1PTEN),
+       SR_TRAP(SYS_CNTP_CVAL_EL0,      CGT_CNTHCTL_EL1PTEN),
+       SR_TRAP(SYS_CNTP_CTL_EL0,       CGT_CNTHCTL_EL1PTEN),
+       SR_TRAP(SYS_CNTPCT_EL0,         CGT_CNTHCTL_EL1PCTEN),
+       SR_TRAP(SYS_CNTPCTSS_EL0,       CGT_CNTHCTL_EL1PCTEN),
 };
 
 static DEFINE_XARRAY(sr_forward_xa);