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devvmx: skip tsc offset writing if CPU doesn't support it

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Sigrid Solveig Haflínudóttir 2021-09-13 22:54:05 +00:00
parent c7dcc82b0b
commit 4f310b8f51
1 changed files with 8 additions and 4 deletions
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12
sys/src/9/pc/devvmx.c
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@ -267,6 +267,7 @@ struct Vmx {
char errstr[ERRMAX];
Ureg ureg;
uvlong tscoffset;
u32int procbctls;
uintptr cr2;
uintptr xcr0;
uintptr dr[8]; /* DR7 is also kept in VMCS */
@ -962,6 +963,7 @@ vmcsinit(Vmx *vmx)
x |= PROCB_USECTLS2;
x &= msr >> 32;
vmcswrite(PROCB_CTLS, x);
vmx->procbctls = x;
if(rdmsr(VMX_PROCB_CTLS2_MSR, &msr) < 0) error("rdmsr(VMX_PROCB_CTLS2_MSR failed");
x = PROCB_EPT | PROCB_VPID | PROCB_UNRESTR;
@ -1062,9 +1064,11 @@ vmcsinit(Vmx *vmx)
vmcswrite(VMEXIT_MSRSTADDR, PADDR(vmx->msrguest));
vmcswrite(VMEXIT_MSRLDADDR, PADDR(vmx->msrhost));
vmcswrite(MSR_BITMAP, PADDR(vmx->msrbits));
cycles(&vmx->tscoffset);
vmcswrite(VMCS_TSC_OFFSET, vmx->tscoffset);
if(vmx->procbctls & PROCB_TSCOFFSET){
cycles(&vmx->tscoffset);
vmcswrite(VMCS_TSC_OFFSET, vmx->tscoffset);
}
if(sizeof(uintptr) == 8){
vmxaddmsr(vmx, Star, 0);
@ -1682,7 +1686,7 @@ vmxproc(void *vmxp)
}
rc = vmlaunch(&vmx->ureg, vmx->launched);
cycles(&end);
useend = 1;
useend = vmx->procbctls & PROCB_TSCOFFSET;
vmx->cr2 = getcr2();
if(m->xcr0 != 0 && vmx->xcr0 != m->xcr0)
putxcr0(m->xcr0);