hw/intc/arm_gicv3_its: Implement MOVI

Implement the ITS MOVI command. This command specifies a (physical) LPI
by DeviceID and EventID and provides a new ICID for it. The ITS must
find the interrupt translation table entry for the LPI, which will
tell it the old ICID. It then moves the pending state of the LPI from
the old redistributor to the new one and updates the ICID field in
the translation table entry.

This is another GICv3 ITS command that we forgot to implement.  Linux
does use this one, but only if the guest powers off one of its CPUs.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220122182444.724087-15-peter.maydell@linaro.org

1 files changed, 53 insertions, 0 deletions

diff --git a/hw/intc/arm_gicv3_redist.c b/hw/intc/arm_gicv3_redist.c
index d1645ba22c..412a04f59c 100644
--- a/hw/intc/arm_gicv3_redist.c
+++ b/hw/intc/arm_gicv3_redist.c
@@ -681,6 +681,59 @@ void gicv3_redist_process_lpi(GICv3CPUState *cs, int irq, int level)
     gicv3_redist_lpi_pending(cs, irq, level);
 }
 
+void gicv3_redist_mov_lpi(GICv3CPUState *src, GICv3CPUState *dest, int irq)
+{
+    /*
+     * Move the specified LPI's pending state from the source redistributor
+     * to the destination.
+     *
+     * If LPIs are disabled on dest this is CONSTRAINED UNPREDICTABLE:
+     * we choose to NOP. If LPIs are disabled on source there's nothing
+     * to be transferred anyway.
+     */
+    AddressSpace *as = &src->gic->dma_as;
+    uint64_t idbits;
+    uint32_t pendt_size;
+    uint64_t src_baddr;
+    uint8_t src_pend;
+
+    if (!(src->gicr_ctlr & GICR_CTLR_ENABLE_LPIS) ||
+        !(dest->gicr_ctlr & GICR_CTLR_ENABLE_LPIS)) {
+        return;
+    }
+
+    idbits = MIN(FIELD_EX64(src->gicr_propbaser, GICR_PROPBASER, IDBITS),
+                 GICD_TYPER_IDBITS);
+    idbits = MIN(FIELD_EX64(dest->gicr_propbaser, GICR_PROPBASER, IDBITS),
+                 idbits);
+
+    pendt_size = 1ULL << (idbits + 1);
+    if ((irq / 8) >= pendt_size) {
+        return;
+    }
+
+    src_baddr = src->gicr_pendbaser & R_GICR_PENDBASER_PHYADDR_MASK;
+
+    address_space_read(as, src_baddr + (irq / 8),
+                       MEMTXATTRS_UNSPECIFIED, &src_pend, sizeof(src_pend));
+    if (!extract32(src_pend, irq % 8, 1)) {
+        /* Not pending on source, nothing to do */
+        return;
+    }
+    src_pend &= ~(1 << (irq % 8));
+    address_space_write(as, src_baddr + (irq / 8),
+                        MEMTXATTRS_UNSPECIFIED, &src_pend, sizeof(src_pend));
+    if (irq == src->hpplpi.irq) {
+        /*
+         * We just made this LPI not-pending so only need to update
+         * if it was previously the highest priority pending LPI
+         */
+        gicv3_redist_update_lpi(src);
+    }
+    /* Mark it pending on the destination */
+    gicv3_redist_lpi_pending(dest, irq, 1);
+}
+
 void gicv3_redist_movall_lpis(GICv3CPUState *src, GICv3CPUState *dest)
 {
     /*