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| author | Amit Machhiwal <amachhiw@linux.ibm.com> | 2026-09-15 22:04:16 +0530 |
|---|---|---|
| committer | Madhavan Srinivasan <maddy@linux.ibm.com> | 2026-09-16 13:43:54 +0530 |
| commit | 0a416ee20bcccddf91ca5b63696a23b9d11d73aa (patch) | |
| tree | 05a32516a3ebb46fbdb1cc87f824f1ec99ba6658 | |
| parent | 51938dfa8a51a4f85328413fca9b6e21f9d2d088 (diff) | |
| download | linux-0a416ee20bcccddf91ca5b63696a23b9d11d73aa.tar.gz linux-0a416ee20bcccddf91ca5b63696a23b9d11d73aa.zip | |
KVM: PPC: Book3S HV: fix secure device page leak on uv_page_in() failure
In kvmppc_svm_page_in(), if uv_page_in() fails after
kvmppc_uvmem_get_page() has succeeded, the secure device page is never
released. kvmppc_uvmem_get_page() sets a bit in kvmppc_uvmem_bitmap,
allocates a kvmppc_uvmem_page_pvt struct, marks the GFN as
KVMPPC_GFN_UVMEM_PFN, and calls zone_device_page_init() which sets
refcount=1 and locks the page. The subsequent goto out_finalize skips
the *mig.dst assignment, so migrate_vma_finalize() is a no-op for the
page, and none of those resources are ever reclaimed.
Each occurrence permanently consumes one entry from the firmware-bounded
secure memory pool (kvmppc_uvmem_bitmap), leaks pvt, and leaves the GFN
marked as secure — making it unusable for the lifetime of the VM.
The twin __kvmppc_svm_page_out() already handles the analogous uv_page_out()
failure correctly with unlock_page(dpage); __free_page(dpage). Apply
the same pattern here: unlock_page() followed by put_page(), which
chains through free_zone_device_folio() into kvmppc_uvmem_folio_free()
to clear the bitmap bit, free pvt, and reset the GFN state.
Reachable whenever uv_page_in() returns an error (e.g. UV pool
exhaustion) on any POWER9/10 + Ultravisor/PEF system.
Fixes: ca9f4942670c ("KVM: PPC: Book3S HV: Support for running secure guests")
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Tested-by: R Nageswara Sastry <rnsastry@linux.ibm.com>
Signed-off-by: Amit Machhiwal <amachhiw@linux.ibm.com>
Signed-off-by: Gautam Menghani <gautam@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_uvmem.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c index 5fbb95d90e99..463aef870c4e 100644 --- a/arch/powerpc/kvm/book3s_hv_uvmem.c +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c @@ -779,8 +779,11 @@ static int kvmppc_svm_page_in(struct vm_area_struct *vma, if (spage) { ret = uv_page_in(kvm->arch.lpid, pfn << page_shift, gpa, 0, page_shift); - if (ret) + if (ret) { + unlock_page(dpage); + put_page(dpage); goto out_finalize; + } } } |