Re: [PATCH] KVM: vmx: add mismatched size in vmcs_check32

Paolo Bonzini
2021-04-08T16:28:53Z

On 08/04/21 18:05, Sean Christopherson wrote:
> Add compile-time assertions in vmcs_check32() to disallow accesses to
> 64-bit and 64-bit high fields via vmcs_{read,write}32(). Upper level
> KVM code should never do partial accesses to VMCS fields. KVM handles
> the split accesses automatically in vmcs_{read,write}64() when running
> as a 32-bit kernel.

KVM also uses raw vmread/vmwrite (__vmcs_readl/__vmcs_writel) when
copying to and from the shadow VMCS, so that path will not go through
vmcs_check32 either.

Paolo