[PATCH v2] KVM: SVM: Mark SEV launch secret pages as dirty.

[Cfir Cohen]

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().

Signed-off-by: Cfir Cohen <c...@google.com>
---
Changelog since v1:
 - Updated commit message.

 arch/x86/kvm/svm/sev.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 5573a97f1520..37c47d26b9f7 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -850,7 +850,7 @@ 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 +863,14 @@ static int sev_launch_secret(struct kvm *kvm, struct 
kvm_sev_cmd *argp)
        if (!pages)
                return -ENOMEM;
 
+       /*
+        * The LAUNCH_SECRET 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.
+        */
+       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 +916,11 @@ 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;
 }
-- 
2.28.0.236.gb10cc79966-goog