From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47725) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZwLEh-0000ec-VH for qemu-devel@nongnu.org; Tue, 10 Nov 2015 21:34:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZwLEd-0002zk-Tr for qemu-devel@nongnu.org; Tue, 10 Nov 2015 21:34:11 -0500 From: David Gibson Date: Wed, 11 Nov 2015 13:34:36 +1100 Message-Id: <1447209276-20146-5-git-send-email-david@gibson.dropbear.id.au> In-Reply-To: <1447209276-20146-1-git-send-email-david@gibson.dropbear.id.au> References: <1447209276-20146-1-git-send-email-david@gibson.dropbear.id.au> Subject: [Qemu-devel] [PULL 4/4] spapr: Handle failure of KVM_PPC_ALLOCATE_HTAB ioctl List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: peter.maydell@linaro.org Cc: lvivier@redhat.com, thuth@redhat.com, qemu-devel@nongnu.org, aik@ozlabs.ru, agraf@suse.de, mdroth@linux.vnet.ibm.com, qemu-ppc@nongnu.org, Bharata B Rao , David Gibson From: Bharata B Rao KVM_PPC_ALLOCATE_HTAB ioctl can return -ENOMEM for KVM guests and QEMU never handled this correctly. But this didn't cause any problems till now as KVM_PPC_ALLOCATE_HTAB ioctl returned with smaller than requested HTAB when enough contiguous memory wasn't available in the host. After the proposed kernel change: https://patchwork.ozlabs.org/patch/530501/, KVM_PPC_ALLOCATE_HTAB ioctl will not fallback to lower sized HTAB allocation and will fail if requested HTAB size can't be met. Check for such failures in QEMU and abort appropriately. This will prevent guest kernel from hanging/freezing during early boot by doing graceful exit when host is unable to allocate requested HTAB. Signed-off-by: Bharata B Rao Signed-off-by: David Gibson --- hw/ppc/spapr.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 37d071e..030ee35 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -1021,9 +1021,19 @@ static void spapr_alloc_htab(sPAPRMachineState *spapr) * RAM */ shift = kvmppc_reset_htab(spapr->htab_shift); - - if (shift > 0) { - /* Kernel handles htab, we don't need to allocate one */ + if (shift < 0) { + /* + * For HV KVM, host kernel will return -ENOMEM when requested + * HTAB size can't be allocated. + */ + error_setg(&error_abort, "Failed to allocate HTAB of requested size, try with smaller maxmem"); + } else if (shift > 0) { + /* + * Kernel handles htab, we don't need to allocate one + * + * Older kernels can fall back to lower HTAB shift values, + * but we don't allow booting of such guests. + */ if (shift != spapr->htab_shift) { error_setg(&error_abort, "Failed to allocate HTAB of requested size, try with smaller maxmem"); } @@ -1055,7 +1065,9 @@ static void spapr_reset_htab(sPAPRMachineState *spapr) int index; shift = kvmppc_reset_htab(spapr->htab_shift); - if (shift > 0) { + if (shift < 0) { + error_setg(&error_abort, "Failed to reset HTAB"); + } else if (shift > 0) { if (shift != spapr->htab_shift) { error_setg(&error_abort, "Requested HTAB allocation failed during reset"); } -- 2.5.0