In the Linux kernel, the following vulnerability has been resolved:
KVM: x86: smm: number of GPRs in the SMRAM image depends on the image format
On 64 bit host, if the guest doesn't have X86FEATURELM, KVM will access 16 gprs to 32-bit smram image, causing out-ouf-bound ram access.
On 32 bit host, the rsmloadstate64/entersmmsavestate_64 is compiled out, thus access overflow can't happen.