OrgACRN
/
acrn-hypervisor
mirror of https://github.com/projectacrn/acrn-hypervisor.git
1
0
Fork 0
Code Issues Releases Wiki Activity

hv: vtd: fix improper use of DMAR_GCMD_REG 

The initialization of "dmar_unit->gcmd" shall be done via reading from
Global Status Register rather than Global Command Register.

Rationale:
According to Chapter 10.4.4 Global Command Register in VT-d spec, Global Command
Register is a write-only register to control remapping hardware.
Global Status Register is the corresponding read-only register to report remapping
hardware status.

Tracked-On: #1842
Signed-off-by: Shiqing Gao <shiqing.gao@intel.com>
This commit is contained in:
Shiqing Gao 2019-12-04 14:44:05 +08:00 committed by wenlingz
parent 68ea2cc62e
commit e95b316dd0
1 changed files with 9 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
hypervisor/arch/x86/vtd.c
View File

@ -471,7 +471,15 @@ static int32_t dmar_register_hrhd(struct dmar_drhd_rt *dmar_unit)
dmar_unit->cap = iommu_read64(dmar_unit, DMAR_CAP_REG);
dmar_unit->ecap = iommu_read64(dmar_unit, DMAR_ECAP_REG);
dmar_unit->gcmd = iommu_read32(dmar_unit, DMAR_GCMD_REG);
/*
* The initialization of "dmar_unit->gcmd" shall be done via reading from Global Status Register rather than
* Global Command Register.
* According to Chapter 10.4.4 Global Command Register in VT-d spec, Global Command Register is a write-only
* 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->cap_msagaw = dmar_unit_get_msagw(dmar_unit);