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[Qemu-devel] [PATCH] intel_iommu: relax iq tail check on VTD_GCMD_QIE en
From: |
Ladi Prosek |
Subject: |
[Qemu-devel] [PATCH] intel_iommu: relax iq tail check on VTD_GCMD_QIE enable |
Date: |
Fri, 16 Jun 2017 13:44:43 +0200 |
The VT-d spec (section 6.5.2) prescribes software to zero the
Invalidation Queue Tail Register before enabling the VTD_GCMD_QIE
Global Command Register bit. Windows Server 2012 R2 and possibly
other older Windows versions violate the protocol and set a
non-zero queue tail first, which in effect makes them crash early
on boot with -device intel-iommu,intremap=on.
This commit relaxes the check and instead of failing to enable
VTD_GCMD_QIE with "error: can't enable Queued Invalidation", it
behaves as if the tail register was set just after enabling
VTD_GCMD_QIE (see vtd_handle_iqt_write).
Signed-off-by: Ladi Prosek <address@hidden>
---
hw/i386/intel_iommu.c | 32 +++++++++++++++-----------------
1 file changed, 15 insertions(+), 17 deletions(-)
diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
index 15610b9..f2cb822 100644
--- a/hw/i386/intel_iommu.c
+++ b/hw/i386/intel_iommu.c
@@ -1466,10 +1466,7 @@ static uint64_t vtd_iotlb_flush(IntelIOMMUState *s,
uint64_t val)
return iaig;
}
-static inline bool vtd_queued_inv_enable_check(IntelIOMMUState *s)
-{
- return s->iq_tail == 0;
-}
+static void vtd_fetch_inv_desc(IntelIOMMUState *s);
static inline bool vtd_queued_inv_disable_check(IntelIOMMUState *s)
{
@@ -1483,19 +1480,20 @@ static void vtd_handle_gcmd_qie(IntelIOMMUState *s,
bool en)
VTD_DPRINTF(INV, "Queued Invalidation Enable %s", (en ? "on" : "off"));
if (en) {
- if (vtd_queued_inv_enable_check(s)) {
- s->iq = iqa_val & VTD_IQA_IQA_MASK;
- /* 2^(x+8) entries */
- s->iq_size = 1UL << ((iqa_val & VTD_IQA_QS) + 8);
- s->qi_enabled = true;
- VTD_DPRINTF(INV, "DMAR_IQA_REG 0x%"PRIx64, iqa_val);
- VTD_DPRINTF(INV, "Invalidation Queue addr 0x%"PRIx64 " size %d",
- s->iq, s->iq_size);
- /* Ok - report back to driver */
- vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_QIES);
- } else {
- VTD_DPRINTF(GENERAL, "error: can't enable Queued Invalidation: "
- "tail %"PRIu16, s->iq_tail);
+ s->iq = iqa_val & VTD_IQA_IQA_MASK;
+ /* 2^(x+8) entries */
+ s->iq_size = 1UL << ((iqa_val & VTD_IQA_QS) + 8);
+ s->qi_enabled = true;
+ VTD_DPRINTF(INV, "DMAR_IQA_REG 0x%"PRIx64, iqa_val);
+ VTD_DPRINTF(INV, "Invalidation Queue addr 0x%"PRIx64 " size %d",
+ s->iq, s->iq_size);
+ /* Ok - report back to driver */
+ vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_QIES);
+
+ if (s->iq_tail != 0 &&
+ !(vtd_get_long_raw(s, DMAR_FSTS_REG) & VTD_FSTS_IQE)) {
+ VTD_DPRINTF(INV, "warning: QI enabled with non-zero tail");
+ vtd_fetch_inv_desc(s);
}
} else {
if (vtd_queued_inv_disable_check(s)) {
--
2.9.3
- [Qemu-devel] [PATCH] intel_iommu: relax iq tail check on VTD_GCMD_QIE enable,
Ladi Prosek <=