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Subject[PATCH v2] KVM: SVM: Mark SEV launch secret pages as dirty.
From
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 <cfir@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
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