Thread (11 messages) 11 messages, 3 authors, 2013-09-25

Re: [PATCH] powerpc/kvm: Handle the boundary condition correctly

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2013-08-23 04:28:14

On Fri, 2013-08-23 at 09:01 +0530, Aneesh Kumar K.V wrote:
Alexander Graf [off-list ref] writes:
quoted
On 22.08.2013, at 12:37, Aneesh Kumar K.V wrote:
quoted
From: "Aneesh Kumar K.V" <redacted>
Isn't this you?
Yes. The patches are generated using git format-patch and sent by
git send-email. That's how it always created patches for me. I am not sure if
there is a config I can change to avoid having From:
Don't bother, that's perfectly fine, and git am will do the right thing.

Cheers,
Ben.
quoted
quoted
We should be able to copy upto count bytes
Why?
Without this we end up doing

 +    struct kvm_get_htab_buf {
 +        struct kvm_get_htab_header header;
 +        /*
 +         * Older kernel required one extra byte.
 +         */
 +        unsigned long hpte[3];
 +    } hpte_buf;


even though we are only looking for one hpte entry.

http://mid.gmane.org/1376995766-16526-4-git-send-email-aneesh.kumar@linux.vnet.ibm.com
quoted
Alex
quoted
Signed-off-by: Aneesh Kumar K.V <redacted>
---
arch/powerpc/kvm/book3s_64_mmu_hv.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
index 710d313..0ae6bb6 100644
--- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
@@ -1362,7 +1362,7 @@ static ssize_t kvm_htab_read(struct file *file, char __user *buf,
	lbuf = (unsigned long __user *)buf;

	nb = 0;
-	while (nb + sizeof(hdr) + HPTE_SIZE < count) {
+	while (nb + sizeof(hdr) + HPTE_SIZE <= count) {
		/* Initialize header */
		hptr = (struct kvm_get_htab_header __user *)buf;
		hdr.n_valid = 0;
@@ -1385,7 +1385,7 @@ static ssize_t kvm_htab_read(struct file *file, char __user *buf,
		/* Grab a series of valid entries */
		while (i < kvm->arch.hpt_npte &&
		       hdr.n_valid < 0xffff &&
-		       nb + HPTE_SIZE < count &&
+		       nb + HPTE_SIZE <= count &&
		       record_hpte(flags, hptp, hpte, revp, 1, first_pass)) {
			/* valid entry, write it out */
			++hdr.n_valid;
-- 
1.8.1.2
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