Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
KVM: SEV: Use PFN_DOWN() to simplify "number of pages" math when pinning memory
Use PFN_DOWN() instead of open coded equivalents in sev_pin_memory() to
simplify the code and make it easier to read.
No functional change intended (verified before and after versions of the
generated code are identical).
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Tested-by: Liam Merwick <liam.merwick@oracle.com>
Link: https://patch.msgid.link/20260313003302.3136111-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
+2
-5
+2
-5
arch/x86/kvm/svm/sev.c
+2
-5
arch/x86/kvm/svm/sev.c
···
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int npinned;
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unsigned long total_npages, lock_limit;
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struct page **pages;
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-
unsigned long first, last;
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int ret;
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lockdep_assert_held(&kvm->lock);
···
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/*
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* Calculate the number of pages that need to be pinned to cover the
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-
* entire range. Note! This isn't simply ulen >> PAGE_SHIFT, as KVM
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+
* entire range. Note! This isn't simply PFN_DOWN(ulen), as KVM
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* doesn't require the incoming address+size to be page aligned!
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*/
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first = (uaddr & PAGE_MASK) >> PAGE_SHIFT;
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last = ((uaddr + ulen - 1) & PAGE_MASK) >> PAGE_SHIFT;
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npages = (last - first + 1);
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+
npages = PFN_DOWN(uaddr + ulen - 1) - PFN_DOWN(uaddr) + 1;
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if (npages > INT_MAX)
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return ERR_PTR(-EINVAL);
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