166 lines
6.8 KiB
Diff
166 lines
6.8 KiB
Diff
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From f9d332b1280cd3f6009b59323719548a36a7c52b Mon Sep 17 00:00:00 2001
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From: Daniel Henrique Barboza <dbarboza@redhat.com>
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Date: Mon, 21 Jun 2021 14:40:24 -0400
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Subject: [PATCH 2/4] spapr: Fix EEH capability issue on KVM guest for PCI
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passthru
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RH-Author: Daniel Henrique Barboza <dbarboza@redhat.com>
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Message-id: <20210621144024.199732-2-dbarboza@redhat.com>
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Patchwork-id: 101740
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O-Subject: [RHEL-8.5.0 qemu-kvm PATCH 1/1] spapr: Fix EEH capability issue on KVM guest for PCI passthru
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Bugzilla: 1957866
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RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
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RH-Acked-by: Greg Kurz <gkurz@redhat.com>
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RH-Acked-by: David Gibson <dgibson@redhat.com>
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From: Mahesh Salgaonkar <mahesh@linux.ibm.com>
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With upstream kernel, especially after commit 98ba956f6a389
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("powerpc/pseries/eeh: Rework device EEH PE determination") we see that KVM
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guest isn't able to enable EEH option for PCI pass-through devices anymore.
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[root@atest-guest ~]# dmesg | grep EEH
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[ 0.032337] EEH: pSeries platform initialized
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[ 0.298207] EEH: No capable adapters found: recovery disabled.
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[root@atest-guest ~]#
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So far the linux kernel was assuming pe_config_addr equal to device's
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config_addr and using it to enable EEH on the PE through ibm,set-eeh-option
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RTAS call. Which wasn't the correct way as per PAPR. The linux kernel
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commit 98ba956f6a389 fixed this flow. With that fixed, linux now uses PE
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config address returned by ibm,get-config-addr-info2 RTAS call to enable
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EEH option per-PE basis instead of per-device basis. However this has
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uncovered a bug in qemu where ibm,set-eeh-option is treating PE config
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address as per-device config address.
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Hence in qemu guest with recent kernel the ibm,set-eeh-option RTAS call
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fails with -3 return value indicating that there is no PCI device exist for
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the specified PE config address. The rtas_ibm_set_eeh_option call uses
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pci_find_device() to get the PC device that matches specific bus and devfn
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extracted from PE config address passed as argument. Thus it tries to map
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the PE config address to a single specific PCI device 'bus->devices[devfn]'
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which always results into checking device on slot 0 'bus->devices[0]'.
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This succeeds when there is a pass-through device (vfio-pci) present on
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slot 0. But in cases where there is no pass-through device present in slot
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0, but present in non-zero slots, ibm,set-eeh-option call fails to enable
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the EEH capability.
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hw/ppc/spapr_pci_vfio.c: spapr_phb_vfio_eeh_set_option()
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case RTAS_EEH_ENABLE: {
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PCIHostState *phb;
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PCIDevice *pdev;
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/*
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* The EEH functionality is enabled on basis of PCI device,
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* instead of PE. We need check the validity of the PCI
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* device address.
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*/
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phb = PCI_HOST_BRIDGE(sphb);
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pdev = pci_find_device(phb->bus,
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(addr >> 16) & 0xFF, (addr >> 8) & 0xFF);
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if (!pdev || !object_dynamic_cast(OBJECT(pdev), "vfio-pci")) {
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return RTAS_OUT_PARAM_ERROR;
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}
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hw/pci/pci.c:pci_find_device()
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PCIDevice *pci_find_device(PCIBus *bus, int bus_num, uint8_t devfn)
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{
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bus = pci_find_bus_nr(bus, bus_num);
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if (!bus)
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return NULL;
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return bus->devices[devfn];
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}
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This patch fixes ibm,set-eeh-option to check for presence of any PCI device
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(vfio-pci) under specified bus and enable the EEH if found. The current
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code already makes sure that all the devices on that bus are from same
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iommu group (within same PE) and fail very early if it does not.
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After this fix guest is able to find EEH capable devices and enable EEH
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recovery on it.
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[root@atest-guest ~]# dmesg | grep EEH
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[ 0.048139] EEH: pSeries platform initialized
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[ 0.405115] EEH: Capable adapter found: recovery enabled.
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[root@atest-guest ~]#
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Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
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Signed-off-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
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Message-Id: <162158429107.145117.5843504911924013125.stgit@jupiter>
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Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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(cherry picked from commit ac9ef668321ebb6eb871a0c4dd380fa7d7891b4e)
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Signed-off-by: Daniel Henrique Barboza <dbarboza@redhat.com>
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Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
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---
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hw/ppc/spapr_pci_vfio.c | 40 +++++++++++++++++++++++++++++++++-------
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1 file changed, 33 insertions(+), 7 deletions(-)
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diff --git a/hw/ppc/spapr_pci_vfio.c b/hw/ppc/spapr_pci_vfio.c
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index ecb34aaade..a411b08d60 100644
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--- a/hw/ppc/spapr_pci_vfio.c
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+++ b/hw/ppc/spapr_pci_vfio.c
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@@ -48,6 +48,16 @@ void spapr_phb_vfio_reset(DeviceState *qdev)
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spapr_phb_vfio_eeh_reenable(SPAPR_PCI_HOST_BRIDGE(qdev));
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}
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+static void spapr_eeh_pci_find_device(PCIBus *bus, PCIDevice *pdev,
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+ void *opaque)
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+{
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+ bool *found = opaque;
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+
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+ if (object_dynamic_cast(OBJECT(pdev), "vfio-pci")) {
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+ *found = true;
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+ }
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+}
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+
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int spapr_phb_vfio_eeh_set_option(SpaprPhbState *sphb,
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unsigned int addr, int option)
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{
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@@ -60,17 +70,33 @@ int spapr_phb_vfio_eeh_set_option(SpaprPhbState *sphb,
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break;
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case RTAS_EEH_ENABLE: {
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PCIHostState *phb;
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- PCIDevice *pdev;
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+ bool found = false;
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/*
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- * The EEH functionality is enabled on basis of PCI device,
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- * instead of PE. We need check the validity of the PCI
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- * device address.
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+ * The EEH functionality is enabled per sphb level instead of
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+ * per PCI device. We have already identified this specific sphb
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+ * based on buid passed as argument to ibm,set-eeh-option rtas
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+ * call. Now we just need to check the validity of the PCI
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+ * pass-through devices (vfio-pci) under this sphb bus.
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+ * We have already validated that all the devices under this sphb
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+ * are from same iommu group (within same PE) before comming here.
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+ *
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+ * Prior to linux commit 98ba956f6a389 ("powerpc/pseries/eeh:
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+ * Rework device EEH PE determination") kernel would call
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+ * eeh-set-option for each device in the PE using the device's
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+ * config_address as the argument rather than the PE address.
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+ * Hence if we check validity of supplied config_addr whether
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+ * it matches to this PHB will cause issues with older kernel
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+ * versions v5.9 and older. If we return an error from
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+ * eeh-set-option when the argument isn't a valid PE address
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+ * then older kernels (v5.9 and older) will interpret that as
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+ * EEH not being supported.
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*/
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phb = PCI_HOST_BRIDGE(sphb);
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- pdev = pci_find_device(phb->bus,
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- (addr >> 16) & 0xFF, (addr >> 8) & 0xFF);
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- if (!pdev || !object_dynamic_cast(OBJECT(pdev), "vfio-pci")) {
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+ pci_for_each_device(phb->bus, (addr >> 16) & 0xFF,
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+ spapr_eeh_pci_find_device, &found);
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+
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+ if (!found) {
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return RTAS_OUT_PARAM_ERROR;
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}
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--
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2.27.0
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