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Code Issues Releases Activity

MSR_KGSBASE is no longer saved and restored from the guest MSR save area. This

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behavior was changed in r271888 so update the comment block to reflect this.

MSR_KGSBASE is accessible from the guest without triggering a VM-exit. The
permission bitmap for MSR_KGSBASE is modified by vmx_msr_guest_init() so get
rid of redundant code in vmx_vminit().
This commit is contained in:
Neel Natu 2014-09-20 05:12:34 +00:00
parent 9cf5a6aad8
commit cb44ea41cb
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=271890
1 changed files with 0 additions and 7 deletions
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7
sys/amd64/vmm/intel/vmx.c
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@ -885,12 +885,6 @@ vmx_vminit(struct vm *vm, pmap_t pmap)
* how they are saved/restored so can be directly accessed by the
* guest.
*
* Guest KGSBASE is saved and restored in the guest MSR save area.
* Host KGSBASE is restored before returning to userland from the pcb.
* There will be a window of time when we are executing in the host
* kernel context with a value of KGSBASE from the guest. This is ok
* because the value of KGSBASE is inconsequential in kernel context.
*
* MSR_EFER is saved and restored in the guest VMCS area on a
* VM exit and entry respectively. It is also restored from the
* host VMCS area on a VM exit.
@ -905,7 +899,6 @@ vmx_vminit(struct vm *vm, pmap_t pmap)
guest_msr_rw(vmx, MSR_SYSENTER_CS_MSR) ||
guest_msr_rw(vmx, MSR_SYSENTER_ESP_MSR) ||
guest_msr_rw(vmx, MSR_SYSENTER_EIP_MSR) ||
guest_msr_rw(vmx, MSR_KGSBASE) ||
guest_msr_rw(vmx, MSR_EFER) ||
guest_msr_ro(vmx, MSR_TSC))
panic("vmx_vminit: error setting guest msr access");