[PULL,15/15] s390x/pci: indicate QEMU supports relaxed translation for passthrough

Commit Message

Thomas Huth March 7, 2025, 11:53 a.m. UTC

From: Matthew Rosato <[e-mail]>

Specifying this bit in the guest CLP response indicates that the guest
can optionally choose to skip translation and instead use
identity-mapped operations.

Tested-by: Niklas Schnelle <[e-mail]>
Reviewed-by: Niklas Schnelle <[e-mail]>
Signed-off-by: Matthew Rosato <[e-mail]>
Message-ID: <[e-mail]>
Signed-off-by: Thomas Huth <[e-mail]>
---
 include/hw/s390x/s390-pci-clp.h | 1 +
 hw/s390x/s390-pci-vfio.c        | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

Patch

diff --git a/include/hw/s390x/s390-pci-clp.h b/include/hw/s390x/s390-pci-clp.h
index 03b7f9ba5f7..6a635d693ba 100644
--- a/include/hw/s390x/s390-pci-clp.h
+++ b/include/hw/s390x/s390-pci-clp.h
@@ -158,6 +158,7 @@  typedef struct ClpRspQueryPciGrp {
 #define CLP_RSP_QPCIG_MASK_NOI 0xfff
     uint16_t i;
     uint8_t version;
+#define CLP_RSP_QPCIG_MASK_RTR     0x20
 #define CLP_RSP_QPCIG_MASK_FRAME   0x2
 #define CLP_RSP_QPCIG_MASK_REFRESH 0x1
     uint8_t fr;
diff --git a/hw/s390x/s390-pci-vfio.c b/hw/s390x/s390-pci-vfio.c
index 443e2229127..6236ac7f1e6 100644
--- a/hw/s390x/s390-pci-vfio.c
+++ b/hw/s390x/s390-pci-vfio.c
@@ -238,8 +238,11 @@  static void s390_pci_read_group(S390PCIBusDevice *pbdev,
         pbdev->pci_group = s390_group_create(pbdev->zpci_fn.pfgid, start_gid);
 
         resgrp = &pbdev->pci_group->zpci_group;
+        if (pbdev->rtr_avail) {
+            resgrp->fr |= CLP_RSP_QPCIG_MASK_RTR;
+        }
         if (cap->flags & VFIO_DEVICE_INFO_ZPCI_FLAG_REFRESH) {
-            resgrp->fr = 1;
+            resgrp->fr |= CLP_RSP_QPCIG_MASK_REFRESH;
         }
         resgrp->dasm = cap->dasm;
         resgrp->msia = cap->msi_addr;