diff options
| author | Michael Roth <michael.roth@amd.com> | 2026-01-09 00:46:20 +0300 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2026-01-15 23:31:16 +0300 |
| commit | dcbcc2323c806b55939d765c13d0728421756017 (patch) | |
| tree | 7b6bd7b2aac52548c190309aafaaa72b7aa2add1 | |
| parent | 8622ef05709fbc4903f54cdf1ac8c3725e479dd8 (diff) | |
| download | linux-dcbcc2323c806b55939d765c13d0728421756017.tar.xz | |
KVM: SEV: Document/enforce page-alignment for KVM_SEV_SNP_LAUNCH_UPDATE
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 <vannapurve@google.com>
Tested-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Link: https://patch.msgid.link/20260108214622.1084057-5-michael.roth@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | Documentation/virt/kvm/x86/amd-memory-encryption.rst | 2 | ||||
| -rw-r--r-- | 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); |