Set the SHADOW register to 0, and set the GUEST_HOST_MASK to CR4_VMXE. This ensures that the guest can set the CR4_VMXE in its CR4 copy to 0, which Linux wants to do. This eliminates the patch we used to need in Linux in the early startup assembly code (head_64.S).
Change-Id: I8ee64a5485abef1b5c1d8b07a705f0642335a038 Signed-off-by: Ronald G. Minnich <[email protected]> --- kern/arch/x86/vmm/intel/vmx.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/kern/arch/x86/vmm/intel/vmx.c b/kern/arch/x86/vmm/intel/vmx.c index 5a93c5a..14e0588 100644 --- a/kern/arch/x86/vmm/intel/vmx.c +++ b/kern/arch/x86/vmm/intel/vmx.c @@ -860,7 +860,11 @@ static int vmx_setup_initial_guest_state(struct proc *p, X86_CR0_MP | X86_CR0_ET | X86_CR0_NE); vmcs_writel(GUEST_CR3, rcr3()); vmcs_writel(GUEST_CR4, cr4); - vmcs_writel(CR4_READ_SHADOW, cr4); + /* The only bits that matter in this shadow are those that are + * set in CR4_GUEST_HOST_MASK. TODO: do we need to separate + * the setting of this value from that of + * CR4_GUEST_HOST_MASK? */ + vmcs_writel(CR4_READ_SHADOW, 0); vmcs_writel(GUEST_IA32_EFER, EFER_LME | EFER_LMA | EFER_SCE /*| EFER_FFXSR */ ); vmcs_writel(GUEST_GDTR_BASE, 0); @@ -1096,7 +1100,17 @@ static void vmx_setup_vmcs(struct guest_pcore *gpc) vmcs_write32(VM_ENTRY_CONTROLS, vmcs_config.vmentry_ctrl); vmcs_writel(CR0_GUEST_HOST_MASK, 0); // ~0ul); - vmcs_writel(CR4_GUEST_HOST_MASK, 0); // ~0ul); + + /* Mask some bits in CR4 as host-owned by setting them in this + * VMCS entry. For example, for now, we mark the CR4_VMXE bit + * as host owned. Right now, when Linux boots, it wants to + * set CR4_VMXE to 0 at first, which is fine -- we do not want + * to think about nested virtualization yet. But if we don't + * mark this bit as host owned we get a VMEXIT. Marking + * CR4_VMXE as host owned means that the reads and writes go + * to the CR4_READ_SHADOW, and we've set the bit to 0 + * there. */ + vmcs_writel(CR4_GUEST_HOST_MASK, CR4_VMXE); //kvm_write_tsc(&vmx->gpc, 0); vmcs_writel(TSC_OFFSET, 0); -- 2.8.0.rc3.226.g39d4020 -- You received this message because you are subscribed to the Google Groups "Akaros" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. For more options, visit https://groups.google.com/d/optout.
