From 8991c460be5a0811194fd4d2b49ba7146a23526b Mon Sep 17 00:00:00 2001 From: Ladi Prosek Date: Mon, 19 Jun 2017 09:31:16 +0200 Subject: intel_iommu: relax iq tail check on VTD_GCMD_QIE enable 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 vtd_err_qi_enable, 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 Reviewed-by: Peter Xu Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/i386/intel_iommu.c | 33 +++++++++++++++++++-------------- hw/i386/trace-events | 2 +- 2 files changed, 20 insertions(+), 15 deletions(-) (limited to 'hw/i386') diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c index a9b59bdce5..2ddf3bd5b5 100644 --- a/hw/i386/intel_iommu.c +++ b/hw/i386/intel_iommu.c @@ -1450,10 +1450,7 @@ 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) { @@ -1468,16 +1465,24 @@ static void vtd_handle_gcmd_qie(IntelIOMMUState *s, bool en) trace_vtd_inv_qi_enable(en); 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; - trace_vtd_inv_qi_setup(s->iq, s->iq_size); - /* Ok - report back to driver */ - vtd_set_clear_mask_long(s, DMAR_GSTS_REG, 0, VTD_GSTS_QIES); - } else { - trace_vtd_err_qi_enable(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; + trace_vtd_inv_qi_setup(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) { + /* + * This is a spec violation but Windows guests are known to set up + * Queued Invalidation this way so we allow the write and process + * Invalidation Descriptors right away. + */ + trace_vtd_warn_invalid_qi_tail(s->iq_tail); + if (!(vtd_get_long_raw(s, DMAR_FSTS_REG) & VTD_FSTS_IQE)) { + vtd_fetch_inv_desc(s); + } } } else { if (vtd_queued_inv_disable_check(s)) { diff --git a/hw/i386/trace-events b/hw/i386/trace-events index 5f111d6dde..42d8a7e27a 100644 --- a/hw/i386/trace-events +++ b/hw/i386/trace-events @@ -74,7 +74,7 @@ vtd_err_dmar_slpte_read_error(uint64_t iova, int level) "iova 0x%"PRIx64" level vtd_err_dmar_slpte_perm_error(uint64_t iova, int level, uint64_t slpte, bool is_write) "iova 0x%"PRIx64" level %d slpte 0x%"PRIx64" write %d" vtd_err_dmar_slpte_resv_error(uint64_t iova, int level, uint64_t slpte) "iova 0x%"PRIx64" level %d slpte 0x%"PRIx64 vtd_err_dmar_translate(uint8_t bus, uint8_t slot, uint8_t func, uint64_t iova) "dev %02x:%02x.%02x iova 0x%"PRIx64 -vtd_err_qi_enable(uint16_t tail) "tail 0x%"PRIx16 +vtd_warn_invalid_qi_tail(uint16_t tail) "tail 0x%"PRIx16 vtd_err_qi_disable(uint16_t head, uint16_t tail, int type) "head 0x%"PRIx16" tail 0x%"PRIx16" last_desc_type %d" vtd_err_qi_tail(uint16_t tail, uint16_t size) "tail 0x%"PRIx16" size 0x%"PRIx16 vtd_err_irte(int index, uint64_t lo, uint64_t hi) "index %d low 0x%"PRIx64" high 0x%"PRIx64 -- cgit v1.2.1