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KVM: SEV: shorten comments around sev_clflush_pages

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Very similar content is present in four comments in sev.c.  Unfortunately
there are small differences that make it harder to place the comment
in sev_clflush_pages itself, but at least we can make it more concise.

Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2020-09-23 13:01:33 -04:00
parent 50085beee8
commit 14e3dd8d25
1 changed files with 7 additions and 12 deletions
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19
arch/x86/kvm/svm/sev.c
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@ -446,10 +446,8 @@ 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 the data that was written unencrypted.
*/
sev_clflush_pages(inpages, npages);
@ -805,10 +803,9 @@ 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 read or modify
* the pages; flush the destination too so that future accesses do not
* see stale data.
*/
sev_clflush_pages(src_p, 1);
sev_clflush_pages(dst_p, 1);
@ -870,10 +867,8 @@ static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp)
return PTR_ERR(pages);
/*
* 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.
* Flush (on non-coherent CPUs) before LAUNCH_SECRET encrypts pages in
* place; the cache may contain the data that was written unencrypted.
*/
sev_clflush_pages(pages, n);