From 0a416ee20bcccddf91ca5b63696a23b9d11d73aa Mon Sep 17 00:00:00 2001 From: Amit Machhiwal Date: Tue, 15 Sep 2026 22:04:16 +0530 Subject: [PATCH] KVM: PPC: Book3S HV: fix secure device page leak on uv_page_in() failure MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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) Tested-by: R Nageswara Sastry Signed-off-by: Amit Machhiwal Signed-off-by: Gautam Menghani Signed-off-by: Madhavan Srinivasan --- arch/powerpc/kvm/book3s_hv_uvmem.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) 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; + } } }