In the past, KVM_SEV_SNP_LAUNCH_UPDATE accepted a non-page-aligned 'uaddr' parameter to copy data from, but continuing to support this with new functionality like in-place conversion and hugepages in the pipeline has proven to be more trouble than it is worth, since there are no known users that have been identified who use a non-page-aligned 'uaddr' parameter. Rather than locking guest_memfd into continuing to support this, go ahead and document page-alignment as a requirement and begin enforcing this in the handling function. Reviewed-by: Vishal Annapurve Tested-by: Kai Huang Signed-off-by: Michael Roth --- Documentation/virt/kvm/x86/amd-memory-encryption.rst | 2 +- arch/x86/kvm/svm/sev.c | 6 +++++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/Documentation/virt/kvm/x86/amd-memory-encryption.rst b/Documentation/virt/kvm/x86/amd-memory-encryption.rst index 1ddb6a86ce7f..5a88d0197cb3 100644 --- a/Documentation/virt/kvm/x86/amd-memory-encryption.rst +++ b/Documentation/virt/kvm/x86/amd-memory-encryption.rst @@ -523,7 +523,7 @@ Returns: 0 on success, < 0 on error, -EAGAIN if caller should retry struct kvm_sev_snp_launch_update { __u64 gfn_start; /* Guest page number to load/encrypt data into. */ - __u64 uaddr; /* Userspace address of data to be loaded/encrypted. */ + __u64 uaddr; /* 4k-aligned address of data to be loaded/encrypted. */ __u64 len; /* 4k-aligned length in bytes to copy into guest memory.*/ __u8 type; /* The type of the guest pages being initialized. */ __u8 pad0; diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index a70bd3f19e29..b4409bc652d1 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -2367,6 +2367,11 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp) params.type != KVM_SEV_SNP_PAGE_TYPE_CPUID)) return -EINVAL; + src = params.type == KVM_SEV_SNP_PAGE_TYPE_ZERO ? NULL : u64_to_user_ptr(params.uaddr); + + if (!PAGE_ALIGNED(src)) + return -EINVAL; + npages = params.len / PAGE_SIZE; /* @@ -2398,7 +2403,6 @@ static int snp_launch_update(struct kvm *kvm, struct kvm_sev_cmd *argp) sev_populate_args.sev_fd = argp->sev_fd; sev_populate_args.type = params.type; - src = params.type == KVM_SEV_SNP_PAGE_TYPE_ZERO ? NULL : u64_to_user_ptr(params.uaddr); count = kvm_gmem_populate(kvm, params.gfn_start, src, npages, sev_gmem_post_populate, &sev_populate_args); -- 2.25.1