@@ -1,2 +1,2 @@
-obj-y += vpci.o header.o
+obj-y += vpci.o header.o rebar.o
obj-$(CONFIG_HAS_PCI_MSI) += msi.o msix.o
new file mode 100644
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2024 Advanced Micro Devices, Inc. All Rights Reserved.
+ *
+ * Author: Jiqian Chen <Jiqian.Chen@amd.com>
+ */
+
+#include <xen/sched.h>
+#include <xen/vpci.h>
+
+static void cf_check rebar_ctrl_write(const struct pci_dev *pdev,
+ unsigned int reg,
+ uint32_t val,
+ void *data)
+{
+ struct vpci_bar *bar = data;
+ uint64_t size = PCI_REBAR_CTRL_SIZE(val);
+
+ if ( bar->enabled )
+ {
+ /*
+ * Refuse to resize a BAR while memory decoding is enabled, as
+ * otherwise the size of the mapped region in the p2m would become
+ * stale with the newly set BAR size, and the position of the BAR
+ * would be reset to undefined. Note the PCIe specification also
+ * forbids resizing a BAR with memory decoding enabled.
+ */
+ if ( size != bar->size )
+ gprintk(XENLOG_ERR,
+ "%pp: refuse to resize BAR with memory decoding enabled\n",
+ &pdev->sbdf);
+ return;
+ }
+
+ if ( !((size >> PCI_REBAR_SIZE_BIAS) & bar->resizable_sizes) )
+ gprintk(XENLOG_WARNING,
+ "%pp: new size %#lx is not supported by hardware\n",
+ &pdev->sbdf, size);
+
+ bar->size = size;
+ bar->addr = 0;
+ bar->guest_addr = 0;
+ pci_conf_write32(pdev->sbdf, reg, val);
+}
+
+static int cf_check init_rebar(struct pci_dev *pdev)
+{
+ uint32_t ctrl;
+ unsigned int nbars;
+ unsigned int rebar_offset = pci_find_ext_capability(pdev->sbdf,
+ PCI_EXT_CAP_ID_REBAR);
+
+ if ( !rebar_offset )
+ return 0;
+
+ if ( !is_hardware_domain(pdev->domain) )
+ {
+ printk(XENLOG_ERR "%pp: resizable BARs unsupported for unpriv %pd\n",
+ &pdev->sbdf, pdev->domain);
+ return -EOPNOTSUPP;
+ }
+
+ ctrl = pci_conf_read32(pdev->sbdf, rebar_offset + PCI_REBAR_CTRL(0));
+ nbars = MASK_EXTR(ctrl, PCI_REBAR_CTRL_NBAR_MASK);
+
+ for ( unsigned int i = 0; i < nbars; i++ )
+ {
+ int rc;
+ struct vpci_bar *bar;
+ unsigned int index;
+
+ ctrl = pci_conf_read32(pdev->sbdf, rebar_offset + PCI_REBAR_CTRL(i));
+ index = ctrl & PCI_REBAR_CTRL_BAR_IDX;;
+ if ( index >= PCI_HEADER_NORMAL_NR_BARS )
+ {
+ /*
+ * TODO: for failed pathes, need to hide ReBar capability
+ * from hardware domain instead of returning an error.
+ */
+ printk(XENLOG_ERR "%pd %pp: too big BAR number %u in REBAR_CTRL\n",
+ pdev->domain, &pdev->sbdf, index);
+ return -EINVAL;
+ }
+
+ bar = &pdev->vpci->header.bars[index];
+ if ( bar->type != VPCI_BAR_MEM64_LO && bar->type != VPCI_BAR_MEM32 )
+ {
+ printk(XENLOG_ERR "%pd %pp: BAR%u is not in memory space\n",
+ pdev->domain, &pdev->sbdf, index);
+ return -EINVAL;
+ }
+
+ rc = vpci_add_register(pdev->vpci, vpci_hw_read32, vpci_hw_write32,
+ rebar_offset + PCI_REBAR_CAP(i), 4, NULL);
+ if ( rc )
+ {
+ printk(XENLOG_ERR "%pd %pp: fail to add reg of REBAR_CAP rc=%d\n",
+ pdev->domain, &pdev->sbdf, rc);
+ return rc;
+ }
+
+ rc = vpci_add_register(pdev->vpci, vpci_hw_read32, rebar_ctrl_write,
+ rebar_offset + PCI_REBAR_CTRL(i), 4, bar);
+ if ( rc )
+ {
+ printk(XENLOG_ERR "%pd %pp: fail to add reg of REBAR_CTRL rc=%d\n",
+ pdev->domain, &pdev->sbdf, rc);
+ return rc;
+ }
+
+ bar->resizable_sizes |=
+ (pci_conf_read32(pdev->sbdf, rebar_offset + PCI_REBAR_CAP(i)) >>
+ PCI_REBAR_CAP_SHIFT);
+ bar->resizable_sizes |=
+ ((uint64_t)MASK_EXTR(ctrl, PCI_REBAR_CTRL_SIZES) <<
+ (32 - PCI_REBAR_CAP_SHIFT));
+ }
+
+ return 0;
+}
+REGISTER_VPCI_INIT(init_rebar, VPCI_PRIORITY_LOW);
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
@@ -232,6 +232,12 @@ void cf_check vpci_hw_write16(
pci_conf_write16(pdev->sbdf, reg, val);
}
+void cf_check vpci_hw_write32(
+ const struct pci_dev *pdev, unsigned int reg, uint32_t val, void *data)
+{
+ pci_conf_write32(pdev->sbdf, reg, val);
+}
+
int vpci_add_register_mask(struct vpci *vpci, vpci_read_t *read_handler,
vpci_write_t *write_handler, unsigned int offset,
unsigned int size, void *data, uint32_t ro_mask,
@@ -459,6 +459,7 @@
#define PCI_EXT_CAP_ID_ARI 14
#define PCI_EXT_CAP_ID_ATS 15
#define PCI_EXT_CAP_ID_SRIOV 16
+#define PCI_EXT_CAP_ID_REBAR 21 /* Resizable BAR */
/* Advanced Error Reporting */
#define PCI_ERR_UNCOR_STATUS 4 /* Uncorrectable Error Status */
@@ -541,6 +542,19 @@
#define PCI_VNDR_HEADER_REV(x) (((x) >> 16) & 0xf)
#define PCI_VNDR_HEADER_LEN(x) (((x) >> 20) & 0xfff)
+/* Resizable BARs */
+#define PCI_REBAR_SIZE_BIAS 20
+#define PCI_REBAR_CAP(n) (4 + 8 * (n)) /* capability register */
+#define PCI_REBAR_CAP_SHIFT 4 /* shift for supported BAR sizes */
+#define PCI_REBAR_CTRL(n) (8 + 8 * (n)) /* control register */
+#define PCI_REBAR_CTRL_BAR_IDX 0x00000007 /* BAR index */
+#define PCI_REBAR_CTRL_NBAR_MASK 0x000000E0 /* # of resizable BARs */
+#define PCI_REBAR_CTRL_BAR_SIZE 0x00001F00 /* BAR size */
+#define PCI_REBAR_CTRL_SIZE(v) \
+ (1UL << (MASK_EXTR(v, PCI_REBAR_CTRL_BAR_SIZE) \
+ + PCI_REBAR_SIZE_BIAS))
+#define PCI_REBAR_CTRL_SIZES 0xFFFF0000U /* supported BAR sizes */
+
/*
* Hypertransport sub capability types
*
@@ -78,6 +78,8 @@ uint32_t cf_check vpci_hw_read32(
const struct pci_dev *pdev, unsigned int reg, void *data);
void cf_check vpci_hw_write16(
const struct pci_dev *pdev, unsigned int reg, uint32_t val, void *data);
+void cf_check vpci_hw_write32(
+ const struct pci_dev *pdev, unsigned int reg, uint32_t val, void *data);
/*
* Check for pending vPCI operations on this vcpu. Returns true if the vcpu
@@ -100,6 +102,7 @@ struct vpci {
/* Guest address. */
uint64_t guest_addr;
uint64_t size;
+ uint64_t resizable_sizes;
struct rangeset *mem;
enum {
VPCI_BAR_EMPTY,
Some devices, like discrete GPU of amd, support resizable bar capability, but vpci of Xen doesn't support this feature, so they fail to resize bars and then cause probing failure. According to PCIe spec, each bar that supports resizing has two registers, PCI_REBAR_CAP and PCI_REBAR_CTRL. So, add handlers for them to support resizing the size of BARs. Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com> --- Hi all, v3->v4 changes: * Removed PCI_REBAR_CAP_SIZES since it was not needed, and added PCI_REBAR_CAP_SHIFT and PCI_REBAR_CTRL_SIZES. * Added parameter resizable_sizes to struct vpci_bar to cache the support resizable sizes and added the logic in init_rebar(). * Changed PCI_REBAR_CAP to PCI_REBAR_CAP(n) (4+8*(n)), changed PCI_REBAR_CTRL to PCI_REBAR_CTRL(n) (8+8*(n)). * Added domain info of pci_dev to printings of init_rebar(). Best regards, Jiqian Chen. v2->v3 changes: * Used "bar->enabled" to replace "pci_conf_read16(pdev->sbdf, PCI_COMMAND) & PCI_COMMAND_MEMORY", and added comments why it needs this check. * Added "!is_hardware_domain(pdev->domain)" check in init_rebar() to return EOPNOTSUPP for domUs. * Moved BAR type and index check into init_rebar(), then only need to check once. * Added 'U' suffix for macro PCI_REBAR_CAP_SIZES. * Added macro PCI_REBAR_SIZE_BIAS to represent 20. TODO: need to hide ReBar capability from hardware domain when init_rebar() fails. v1->v2 changes: * In rebar_ctrl_write, to check if memory decoding is enabled, and added some checks for the type of Bar. * Added vpci_hw_write32 to handle PCI_REBAR_CAP's write, since there is no write limitation of dom0. * And has many other minor modifications as well. --- xen/drivers/vpci/Makefile | 2 +- xen/drivers/vpci/rebar.c | 131 +++++++++++++++++++++++++++++++++++++ xen/drivers/vpci/vpci.c | 6 ++ xen/include/xen/pci_regs.h | 14 ++++ xen/include/xen/vpci.h | 3 + 5 files changed, 155 insertions(+), 1 deletion(-) create mode 100644 xen/drivers/vpci/rebar.c