The LAUNCH_SECRET command performs encryption of the launch secret memory contents. Mark pinned pages as dirty, before unpinning them. This matches the logic in sev_launch_update_data().

Fixes: 9c5e0afaf157 ("KVM: SVM: Add support for SEV LAUNCH_SECRET command") Signed-off-by: Cfir Cohen cfir@google.com --- Changelog since v2: - Added 'Fixes' tag, updated comments. Changelog since v1: - Updated commit message.

arch/x86/kvm/svm/sev.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 5573a97f1520..55edaf3577a0 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -440,10 +440,8 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp) }

/* - * The LAUNCH_UPDATE command will perform in-place encryption of the - * memory content (i.e it will write the same memory region with C=1). - * It's possible that the cache may contain the data with C=0, i.e., - * unencrypted so invalidate it first. + * Flush (on non-coherent CPUs) before LAUNCH_UPDATE encrypts pages in + * place, the cache may contain data that was written unencrypted. */ sev_clflush_pages(inpages, npages);

@@ -799,10 +797,9 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec) }

/* - * The DBG_{DE,EN}CRYPT commands will perform {dec,en}cryption of the - * memory content (i.e it will write the same memory region with C=1). - * It's possible that the cache may contain the data with C=0, i.e., - * unencrypted so invalidate it first. + * Flush (on non-coherent CPUs) before DBG_{DE,EN}CRYPT reads or modifies + * the pages, flush the destination too in case the cache contains its + * current data. */ sev_clflush_pages(src_p, 1); sev_clflush_pages(dst_p, 1); @@ -850,7 +847,7 @@ static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp) struct kvm_sev_launch_secret params; struct page **pages; void *blob, *hdr; - unsigned long n; + unsigned long n, i; int ret, offset;

if (!sev_guest(kvm)) @@ -863,6 +860,12 @@ static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp) if (!pages) return -ENOMEM;

+ /* + * Flush (on non-coherent CPUs) before LAUNCH_SECRET encrypts pages in + * place, the cache may contain data that was written unencrypted. + */ + sev_clflush_pages(pages, n); + /* * The secret must be copied into contiguous memory region, lets verify * that userspace memory pages are contiguous before we issue command. @@ -908,6 +911,11 @@ static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp) e_free: kfree(data); e_unpin_memory: + /* content of memory is updated, mark pages dirty */ + for (i = 0; i < n; i++) { + set_page_dirty_lock(pages[i]); + mark_page_accessed(pages[i]); + } sev_unpin_memory(kvm, pages, n); return ret; }