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hv: vtd: reset the one-shot bits for GCMD_REG

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If multiple control fields in GCMD_REG register need to be modified, software
must serialize the modifications through multiple writes to this register.

So one-shot bits (bits 30-29, 27 and 24) in gcmd should not been set.
Otherwise, other control field may be written to GCMD_REG at the same time
with one-shot bit (Clearing one-shot bit has no effect, software sets this field
would set/update this control field used by hardware).

Tracked-On: #7381
Signed-off-by: Fei Li <fei1.li@intel.com>
This commit is contained in:
Fei Li 2022-04-29 17:19:54 +08:00 committed by acrnsi-robot
parent 5f0588b5f8
commit df3390f401
1 changed files with 1 additions and 1 deletions
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2
hypervisor/arch/x86/vtd.c
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@ -446,7 +446,7 @@ static int32_t dmar_register_hrhd(struct dmar_drhd_rt *dmar_unit)
* register to control remapping hardware. Global Status Register is the corresponding read-only register to
* report remapping hardware status.
*/
dmar_unit->gcmd = iommu_read32(dmar_unit, DMAR_GSTS_REG);
dmar_unit->gcmd = iommu_read32(dmar_unit, DMAR_GSTS_REG) & 0x96FFFFFFU; // Reset the one-shot bits;
dmar_unit->cap_msagaw = dmar_unit_get_msagw(dmar_unit);