[PATCH v2 08/14] ppc/xive2: Support "Pull Thread Context to Register" operation

[Michael Kowal <kowal@linux.ibm.com>]

From: Glenn Miles <milesg@linux.vnet.ibm.com>

Adds support for single byte read of offset 0x838 of the TIMA address
space.  According to the XIVE2 Specification, this causes the hardware
to atomically:
  1. Read the number of bytes requested (lbz or lhz are supported).
  2. Reset the valid bit of the thread context.
  3. Return the number of bytes requested in step 1 to a register.

Signed-off-by: Glenn Miles <milesg@linux.vnet.ibm.com>
Signed-off-by: Michael Kowal <kowal@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
---
 include/hw/ppc/xive_regs.h |  2 ++
 hw/intc/xive.c             | 15 +++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/hw/ppc/xive_regs.h b/include/hw/ppc/xive_regs.h
index f8f05deafd..558a5ae742 100644
--- a/include/hw/ppc/xive_regs.h
+++ b/include/hw/ppc/xive_regs.h
@@ -101,6 +101,7 @@
 #define   TM_QW3W2_LP           PPC_BIT32(6)
 #define   TM_QW3W2_LE           PPC_BIT32(7)
 #define   TM_QW3W2_T            PPC_BIT32(31)
+#define   TM_QW3B8_VT           PPC_BIT8(0)
 
 /*
  * In addition to normal loads to "peek" and writes (only when invalid)
@@ -128,6 +129,7 @@
 #define TM_SPC_PULL_POOL_CTX    0x828   /* Load32/Load64 Pull/Invalidate Pool */
                                         /* context to reg                     */
 #define TM_SPC_ACK_HV_REG       0x830   /* Load16 ack HV irq to reg           */
+#define TM_SPC_PULL_PHYS_CTX    0x838   /* Pull phys ctx to reg               */
 #define TM_SPC_PULL_USR_CTX_OL  0xc08   /* Store8 Pull/Inval usr ctx to odd   */
                                         /* line                               */
 #define TM_SPC_ACK_OS_EL        0xc10   /* Store8 ack OS irq to even line     */
diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index 6229a6f870..5b66a3aec5 100644
--- a/hw/intc/xive.c
+++ b/hw/intc/xive.c
@@ -179,6 +179,17 @@ static uint64_t xive_tm_pull_pool_ctx(XivePresenter *xptr, XiveTCTX *tctx,
     return qw2w2;
 }
 
+static uint64_t xive_tm_pull_phys_ctx(XivePresenter *xptr, XiveTCTX *tctx,
+                                      hwaddr offset, unsigned size)
+{
+    uint8_t qw3b8_prev = tctx->regs[TM_QW3_HV_PHYS + TM_WORD2];
+    uint8_t qw3b8;
+
+    qw3b8 = qw3b8_prev & ~TM_QW3B8_VT;
+    tctx->regs[TM_QW3_HV_PHYS + TM_WORD2] = qw3b8;
+    return qw3b8;
+}
+
 static void xive_tm_vt_push(XivePresenter *xptr, XiveTCTX *tctx, hwaddr offset,
                             uint64_t value, unsigned size)
 {
@@ -527,6 +538,8 @@ static const XiveTmOp xive_tm_operations[] = {
                                                      xive_tm_pull_pool_ctx },
     { XIVE_TM_HV_PAGE, TM_SPC_PULL_POOL_CTX,      8, NULL,
                                                      xive_tm_pull_pool_ctx },
+    { XIVE_TM_HV_PAGE, TM_SPC_PULL_PHYS_CTX,      1, NULL,
+                                                     xive_tm_pull_phys_ctx },
 };
 
 static const XiveTmOp xive2_tm_operations[] = {
@@ -566,6 +579,8 @@ static const XiveTmOp xive2_tm_operations[] = {
                                                      xive_tm_pull_pool_ctx },
     { XIVE_TM_HV_PAGE, TM_SPC_PULL_OS_CTX_OL,     1, xive2_tm_pull_os_ctx_ol,
                                                      NULL },
+    { XIVE_TM_HV_PAGE, TM_SPC_PULL_PHYS_CTX,      1, NULL,
+                                                     xive_tm_pull_phys_ctx },
 };
 
 static const XiveTmOp *xive_tm_find_op(XivePresenter *xptr, hwaddr offset,
-- 
2.43.0