linux-kernel - [PATCH 5.6 106/118] arch/x86/kvm/svm/sev.c: change flag passed to GUP fast in sev_pin

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Message-Id: <20200513094427.166204184@linuxfoundation.org>
Date:   Wed, 13 May 2020 11:45:25 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Janakarajan Natarajan <Janakarajan.Natarajan@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Ira Weiny <ira.weiny@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Mike Marshall <hubcap@...ibond.com>,
        Brijesh Singh <brijesh.singh@....com>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 5.6 106/118] arch/x86/kvm/svm/sev.c: change flag passed to GUP fast in sev_pin_memory()

From: Janakarajan Natarajan <Janakarajan.Natarajan@....com>

commit 996ed22c7a5251d76dcdfe5026ef8230e90066d9 upstream.

When trying to lock read-only pages, sev_pin_memory() fails because
FOLL_WRITE is used as the flag for get_user_pages_fast().

Commit 73b0140bf0fe ("mm/gup: change GUP fast to use flags rather than a
write 'bool'") updated the get_user_pages_fast() call sites to use
flags, but incorrectly updated the call in sev_pin_memory().  As the
original coding of this call was correct, revert the change made by that
commit.

Fixes: 73b0140bf0fe ("mm/gup: change GUP fast to use flags rather than a write 'bool'")
Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@....com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@...el.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Sean Christopherson <sean.j.christopherson@...el.com>
Cc: Vitaly Kuznetsov <vkuznets@...hat.com>
Cc: Wanpeng Li <wanpengli@...cent.com>
Cc: Jim Mattson <jmattson@...gle.com>
Cc: Joerg Roedel <joro@...tes.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H . Peter Anvin" <hpa@...or.com>
Cc: Mike Marshall <hubcap@...ibond.com>
Cc: Brijesh Singh <brijesh.singh@....com>
Link: http://lkml.kernel.org/r/20200423152419.87202-1-Janakarajan.Natarajan@amd.com
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/x86/kvm/svm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1886,7 +1886,7 @@ static struct page **sev_pin_memory(stru
 		return NULL;

 	/* Pin the user virtual address. */
-	npinned = get_user_pages_fast(uaddr, npages, FOLL_WRITE, pages);
+	npinned = get_user_pages_fast(uaddr, npages, write ? FOLL_WRITE : 0, pages);
 	if (npinned != npages) {
 		pr_err("SEV: Failure locking %lu pages.\n", npages);
 		goto err;