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Subject[PATCH] KVM: x86: report sev_pin_memory errors with PTR_ERR
Date
Callers of sev_pin_memory() treat
NULL differently:

sev_launch_secret()/svm_register_enc_region() return -ENOMEM
sev_dbg_crypt() returns -EFAULT.

Switching to ERR_PTR() preserves the error and enables cleaner reporting of
different kinds of failures.

Suggested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/svm/sev.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index a893624b9275..2b4916ffa906 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -320,7 +320,7 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr,
unsigned long first, last;

if (ulen == 0 || uaddr + ulen < uaddr)
- return NULL;
+ return ERR_PTR(-EINVAL);

/* Calculate number of pages. */
first = (uaddr & PAGE_MASK) >> PAGE_SHIFT;
@@ -331,11 +331,11 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr,
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
if (locked > lock_limit && !capable(CAP_IPC_LOCK)) {
pr_err("SEV: %lu locked pages exceed the lock limit of %lu.\n", locked, lock_limit);
- return NULL;
+ return ERR_PTR(-ENOMEM);
}

if (WARN_ON_ONCE(npages > INT_MAX))
- return NULL;
+ return ERR_PTR(-EINVAL);

/* Avoid using vmalloc for smaller buffers. */
size = npages * sizeof(struct page *);
@@ -345,7 +345,7 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr,
pages = kmalloc(size, GFP_KERNEL_ACCOUNT);

if (!pages)
- return NULL;
+ return ERR_PTR(-ENOMEM);

/* Pin the user virtual address. */
npinned = pin_user_pages_fast(uaddr, npages, write ? FOLL_WRITE : 0, pages);
@@ -360,11 +360,13 @@ static struct page **sev_pin_memory(struct kvm *kvm, unsigned long uaddr,
return pages;

err:
- if (npinned > 0)
+ if (npinned > 0) {
unpin_user_pages(pages, npinned);
+ npinned = -ENOMEM;
+ }

kvfree(pages);
- return NULL;
+ return ERR_PTR(npinned);
}

static void sev_unpin_memory(struct kvm *kvm, struct page **pages,
@@ -864,8 +866,8 @@ static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp)
return -EFAULT;

pages = sev_pin_memory(kvm, params.guest_uaddr, params.guest_len, &n, 1);
- if (!pages)
- return -ENOMEM;
+ if (IS_ERR(pages))
+ return PTR_ERR(pages);

/*
* The secret must be copied into contiguous memory region, lets verify
@@ -991,8 +993,8 @@ int svm_register_enc_region(struct kvm *kvm,
return -ENOMEM;

region->pages = sev_pin_memory(kvm, range->addr, range->size, &region->npages, 1);
- if (!region->pages) {
- ret = -ENOMEM;
+ if (IS_ERR(region->pages)) {
+ ret = PTR_ERR(region->pages);
goto e_free;
}

--
2.26.2
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