Make sure the MSIX MMIO regions don't have p2m entries setup, so that
accesses to them trap into the hypervisor and can be handled by vpci.
This is a side-effect of commit 042678762 for PVH Dom0, which added
mappings for all the reserved regions into the Dom0 p2m.
Signed-off-by: Roger Pau Monné <roger....@citrix.com>
---
Cc: Andrew Cooper <andrew.coop...@citrix.com>
Cc: George Dunlap <george.dun...@eu.citrix.com>
Cc: Ian Jackson <ian.jack...@eu.citrix.com>
Cc: Jan Beulich <jbeul...@suse.com>
Cc: Julien Grall <julien.gr...@arm.com>
Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Cc: Stefano Stabellini <sstabell...@kernel.org>
Cc: Tim Deegan <t...@xen.org>
Cc: Wei Liu <wei.l...@citrix.com>
---
xen/drivers/vpci/header.c | 8 ++++++++
xen/drivers/vpci/msix.c | 40 +++++++++++++++++++++++++++++++++++++++
xen/include/xen/vpci.h | 3 +++
3 files changed, 51 insertions(+)
diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
index 4af85d3c02..455dd4fc90 100644
--- a/xen/drivers/vpci/header.c
+++ b/xen/drivers/vpci/header.c
@@ -88,6 +88,14 @@ static void modify_decoding(const struct pci_dev *pdev, bool
map, bool rom_only)
uint16_t cmd;
unsigned int i;
+ /*
+ * Make sure there are no mappings in the MSIX MMIO areas, so that accesses
+ * can be trapped (and emulated) by Xen when the memory decoding bit is
+ * enabled.
+ */
+ if ( map && !rom_only && vpci_make_msix_hole(pdev) )
+ return;
+
for ( i = 0; i < ARRAY_SIZE(header->bars); i++ )
{
if ( !MAPPABLE_BAR(&header->bars[i]) )
diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c
index 1960dae123..5759551724 100644
--- a/xen/drivers/vpci/msix.c
+++ b/xen/drivers/vpci/msix.c
@@ -21,6 +21,7 @@
#include <xen/vpci.h>
#include <asm/msi.h>
+#include <asm/p2m.h>
#define VMSIX_SIZE(num) offsetof(struct vpci_msix, entries[num])
@@ -395,6 +396,45 @@ static const struct hvm_mmio_ops vpci_msix_table_ops = {
.write = msix_write,
};
+int vpci_make_msix_hole(const struct pci_dev *pdev)
+{
+ struct domain *d = pdev->domain;
+ unsigned int i;
+
+ if ( !pdev->vpci->msix )
+ return 0;
+
+ /* Make sure there's a hole for the MSIX table/PBA in the p2m. */
+ for ( i = 0; i < ARRAY_SIZE(pdev->vpci->msix->tables); i++ )
+ {
+ unsigned long start = PFN_DOWN(vmsix_table_addr(pdev->vpci, i));
+ unsigned long end = PFN_DOWN(vmsix_table_addr(pdev->vpci, i) +
+ vmsix_table_size(pdev->vpci, i) - 1);
+
+ for ( ; start <= end; start++ )
+ {
+ p2m_type_t t;
+ mfn_t mfn = get_gfn_query(d, start, &t);
+
+ if ( t == p2m_mmio_direct && mfn_x(mfn) == start )
+ clear_identity_p2m_entry(d, start);
+ else if ( t != p2m_mmio_dm )
+ {
+ put_gfn(d, start);
+ gprintk(XENLOG_WARNING,
+ "%04x:%02x:%02x.%u: existing mapping (mfn: %" PRI_mfn
+ "type: %d) at %#lx clobbers MSIX MMIO area\n",
+ pdev->seg, pdev->bus, PCI_SLOT(pdev->devfn),
+ PCI_FUNC(pdev->devfn), mfn_x(mfn), t, start);
+ return -EEXIST;
+ }
+ put_gfn(d, start);
+ }
+ }
+
+ return 0;
+}
+
static int init_msix(struct pci_dev *pdev)
{
struct domain *d = pdev->domain;
diff --git a/xen/include/xen/vpci.h b/xen/include/xen/vpci.h
index f97c48a8f1..e0c22ad81c 100644
--- a/xen/include/xen/vpci.h
+++ b/xen/include/xen/vpci.h
@@ -151,6 +151,9 @@ struct vpci_vcpu {
#ifdef __XEN__
void vpci_dump_msi(void);
+/* Make sure there's a hole in the p2m for the MSIX mmio areas. */
+int vpci_make_msix_hole(const struct pci_dev *pdev);
+
/* Arch-specific vPCI MSI helpers. */
void vpci_msi_arch_mask(struct vpci_msi *msi, const struct pci_dev *pdev,
unsigned int entry, bool mask);
--
2.19.1
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