KVM: arm/arm64: VGIC: Fix command handling while ITS being disabled

[linux.git] / virt / kvm / arm / vgic / vgic-its.c

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 571b64a01c509741146e5e2263d5042457a2e14c..8d1da1af4b09e47c174cf7151b37b98666f03953 100644 (file)
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -360,29 +360,6 @@ static int its_sync_lpi_pending_table(struct kvm_vcpu *vcpu)
        return ret;
 }
 
-static unsigned long vgic_mmio_read_its_ctlr(struct kvm *vcpu,
-                                            struct vgic_its *its,
-                                            gpa_t addr, unsigned int len)
-{
-       u32 reg = 0;
-
-       mutex_lock(&its->cmd_lock);
-       if (its->creadr == its->cwriter)
-               reg |= GITS_CTLR_QUIESCENT;
-       if (its->enabled)
-               reg |= GITS_CTLR_ENABLE;
-       mutex_unlock(&its->cmd_lock);
-
-       return reg;
-}
-
-static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its,
-                                    gpa_t addr, unsigned int len,
-                                    unsigned long val)
-{
-       its->enabled = !!(val & GITS_CTLR_ENABLE);
-}
-
 static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
                                              struct vgic_its *its,
                                              gpa_t addr, unsigned int len)
@@ -1161,33 +1138,16 @@ static void vgic_mmio_write_its_cbaser(struct kvm *kvm, struct vgic_its *its,
 #define ITS_CMD_SIZE                   32
 #define ITS_CMD_OFFSET(reg)            ((reg) & GENMASK(19, 5))
 
-/*
- * By writing to CWRITER the guest announces new commands to be processed.
- * To avoid any races in the first place, we take the its_cmd lock, which
- * protects our ring buffer variables, so that there is only one user
- * per ITS handling commands at a given time.
- */
-static void vgic_mmio_write_its_cwriter(struct kvm *kvm, struct vgic_its *its,
-                                       gpa_t addr, unsigned int len,
-                                       unsigned long val)
+/* Must be called with the cmd_lock held. */
+static void vgic_its_process_commands(struct kvm *kvm, struct vgic_its *its)
 {
        gpa_t cbaser;
        u64 cmd_buf[4];
-       u32 reg;
 
-       if (!its)
-               return;
-
-       mutex_lock(&its->cmd_lock);
-
-       reg = update_64bit_reg(its->cwriter, addr & 7, len, val);
-       reg = ITS_CMD_OFFSET(reg);
-       if (reg >= ITS_CMD_BUFFER_SIZE(its->cbaser)) {
-               mutex_unlock(&its->cmd_lock);
+       /* Commands are only processed when the ITS is enabled. */
+       if (!its->enabled)
                return;
-       }
 
-       its->cwriter = reg;
        cbaser = CBASER_ADDRESS(its->cbaser);
 
        while (its->cwriter != its->creadr) {
@@ -1207,6 +1167,34 @@ static void vgic_mmio_write_its_cwriter(struct kvm *kvm, struct vgic_its *its,
                if (its->creadr == ITS_CMD_BUFFER_SIZE(its->cbaser))
                        its->creadr = 0;
        }
+}
+
+/*
+ * By writing to CWRITER the guest announces new commands to be processed.
+ * To avoid any races in the first place, we take the its_cmd lock, which
+ * protects our ring buffer variables, so that there is only one user
+ * per ITS handling commands at a given time.
+ */
+static void vgic_mmio_write_its_cwriter(struct kvm *kvm, struct vgic_its *its,
+                                       gpa_t addr, unsigned int len,
+                                       unsigned long val)
+{
+       u64 reg;
+
+       if (!its)
+               return;
+
+       mutex_lock(&its->cmd_lock);
+
+       reg = update_64bit_reg(its->cwriter, addr & 7, len, val);
+       reg = ITS_CMD_OFFSET(reg);
+       if (reg >= ITS_CMD_BUFFER_SIZE(its->cbaser)) {
+               mutex_unlock(&its->cmd_lock);
+               return;
+       }
+       its->cwriter = reg;
+
+       vgic_its_process_commands(kvm, its);
 
        mutex_unlock(&its->cmd_lock);
 }
@@ -1287,6 +1275,39 @@ static void vgic_mmio_write_its_baser(struct kvm *kvm,
        *regptr = reg;
 }
 
+static unsigned long vgic_mmio_read_its_ctlr(struct kvm *vcpu,
+                                            struct vgic_its *its,
+                                            gpa_t addr, unsigned int len)
+{
+       u32 reg = 0;
+
+       mutex_lock(&its->cmd_lock);
+       if (its->creadr == its->cwriter)
+               reg |= GITS_CTLR_QUIESCENT;
+       if (its->enabled)
+               reg |= GITS_CTLR_ENABLE;
+       mutex_unlock(&its->cmd_lock);
+
+       return reg;
+}
+
+static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its,
+                                    gpa_t addr, unsigned int len,
+                                    unsigned long val)
+{
+       mutex_lock(&its->cmd_lock);
+
+       its->enabled = !!(val & GITS_CTLR_ENABLE);
+
+       /*
+        * Try to process any pending commands. This function bails out early
+        * if the ITS is disabled or no commands have been queued.
+        */
+       vgic_its_process_commands(kvm, its);
+
+       mutex_unlock(&its->cmd_lock);
+}
+
 #define REGISTER_ITS_DESC(off, rd, wr, length, acc)            \
 {                                                              \
        .reg_offset = off,                                      \