[Xen-devel] [PATCH v6 7/7] xen/x86: setup PVHv2 Dom0 ACPI tables

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Create a new MADT table that contains the topology exposed to the guest. A
new XSDT table is also created, in order to filter the tables that we want
to expose to the guest, plus the Xen crafted MADT. This in turn requires Xen
to also create a new RSDP in order to make it point to the custom XSDT.

Also, regions marked as E820_ACPI or E820_NVS are identity mapped into Dom0
p2m, plus any top-level ACPI tables that should be accessible to Dom0 and
reside in reserved regions. This is needed because some memory maps don't
properly account for all the memory used by ACPI, so it's common to find ACPI
tables in reserved regions.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
Changes since v5:
 - s/hvm_copy_to_guest_phys_vcpu/hvm_copy_to_guest_phys/.
 - Move pvh_add_mem_range to previous patch.
 - Add a comment regarding the current limitation to only 1 emulated IO APIC.
 - s/dom0_max_vcpus()/max_vcpus/ in pvh_setup_acpi_madt.
 - Cast structures to void when assigning.
 - Declare banned_tables with the initconst annotation.
 - Expand some comments messages.
 - Initialize the RSDP local variable.
 - Only provide x2APIC entries in the MADT.

Changes since v4:
 - s/hvm/pvh.
 - Use hvm_copy_to_guest_phys_vcpu.
 - Don't allocate up to E820MAX entries for the Dom0 memory map and instead
   allow pvh_add_mem_range to dynamically grow the memory map.
 - Add a comment about the lack of x2APIC MADT entries.
 - Change acpi_intr_overrides to unsigned int and the max iterator bound to
   UINT_MAX.
 - Set the MADT version as the minimum version between the hardware value and
   our supported version (4).
 - Set the MADT IO APIC ID to the current value of the domain vioapic->id.
 - Use void * when subtracting two pointers.
 - Fix indentation of nr_pages and use PFN_UP instead of DIV_ROUND_UP.
 - Change wording of the pvh_acpi_table_allowed error message.
 - Make j unsigned in pvh_setup_acpi_xsdt.
 - Move initialization of local variables with declarations in
   pvh_setup_acpi_xsdt.
 - Reword the comment about the allocated size of the xsdt custom table.
 - Fix line splitting.
 - Add a comment regarding the layering violation caused by the usage of
   acpi_tb_checksum.
 - Pass IO APIC NMI sources found in the MADT to Dom0.
 - Create x2APIC entries if the native MADT also contains them.
 - s/acpi_intr_overrrides/acpi_intr_overrides/.
 - Make sure the MADT is properly mapped into Dom0, or else Dom0 might not be
   able to access the output of the _MAT method depending on the
   implementation.
 - Get the first ACPI processor ID and use that as the base processor ID of the
   crafted MADT. This is done so that local/x2 APIC NMI entries match with the
   local/x2 APIC objects.

Changes since v3:
 - Use hvm_copy_to_phys in order to copy the tables to Dom0 memory.
 - Return EEXIST for overlaping ranges in hvm_add_mem_range.
 - s/ov/ovr/ for interrupt override parsing functions.
 - Constify intr local variable in acpi_set_intr_ovr.
 - Use structure asignement for type safety.
 - Perform sizeof using local variables in hvm_setup_acpi_madt.
 - Manually set revision of crafted/modified tables.
 - Only map tables to guest that reside in reserved or ACPI memory regions.
 - Copy the RSDP OEM signature to the crafted RSDP.
 - Pair calls to acpi_os_map_memory/acpi_os_unmap_memory.
 - Add memory regions for allowed ACPI tables to the memory map and then
   perform the identity mappings. This avoids having to call 
modify_identity_mmio
   multiple times.
 - Add a FIXME comment regarding the lack of multiple vIO-APICs.

Changes since v2:
 - Completely reworked.
---
 xen/arch/x86/domain_build.c | 434 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 434 insertions(+)

diff --git a/xen/arch/x86/domain_build.c b/xen/arch/x86/domain_build.c
index 1ff2ddb..85de84f 100644
--- a/xen/arch/x86/domain_build.c
+++ b/xen/arch/x86/domain_build.c
@@ -23,6 +23,7 @@
 #include <xen/libelf.h>
 #include <xen/pfn.h>
 #include <xen/guest_access.h>
+#include <xen/acpi.h>
 #include <asm/regs.h>
 #include <asm/system.h>
 #include <asm/io.h>
@@ -38,6 +39,8 @@
 #include <asm/io_apic.h>
 #include <asm/hpet.h>
 
+#include <acpi/actables.h>
+
 #include <public/version.h>
 #include <public/arch-x86/hvm/start_info.h>
 #include <public/hvm/hvm_info_table.h>
@@ -53,6 +56,12 @@ static long __initdata dom0_max_nrpages = LONG_MAX;
  * */
 #define HVM_VM86_TSS_SIZE   128
 
+static unsigned int __initdata acpi_intr_overrides;
+static struct acpi_madt_interrupt_override __initdata *intsrcovr;
+
+static unsigned int __initdata acpi_nmi_sources;
+static struct acpi_madt_nmi_source __initdata *nmisrc;
+
 /*
  * dom0_mem=[min:<min_amt>,][max:<max_amt>,][<amt>]
  * 
@@ -2196,6 +2205,424 @@ static int __init pvh_setup_cpus(struct domain *d, 
paddr_t entry,
     return 0;
 }
 
+static int __init acpi_count_intr_ovr(struct acpi_subtable_header *header,
+                                     const unsigned long end)
+{
+
+    acpi_intr_overrides++;
+    return 0;
+}
+
+static int __init acpi_set_intr_ovr(struct acpi_subtable_header *header,
+                                    const unsigned long end)
+{
+    const struct acpi_madt_interrupt_override *intr =
+        container_of(header, struct acpi_madt_interrupt_override, header);
+
+    *intsrcovr = *intr;
+    intsrcovr++;
+
+    return 0;
+}
+
+static int __init acpi_count_nmi_src(struct acpi_subtable_header *header,
+                                     const unsigned long end)
+{
+
+    acpi_nmi_sources++;
+    return 0;
+}
+
+static int __init acpi_set_nmi_src(struct acpi_subtable_header *header,
+                                   const unsigned long end)
+{
+    const struct acpi_madt_nmi_source *src =
+        container_of(header, struct acpi_madt_nmi_source, header);
+
+    *nmisrc = *src;
+    nmisrc++;
+
+    return 0;
+}
+
+static int __init pvh_setup_acpi_madt(struct domain *d, paddr_t *addr)
+{
+    struct acpi_table_madt *madt;
+    struct acpi_table_header *table;
+    struct acpi_madt_io_apic *io_apic;
+    struct acpi_madt_local_x2apic *x2apic;
+    acpi_status status;
+    unsigned long size;
+    unsigned int i, max_vcpus;
+    int rc;
+
+    /* Count number of interrupt overrides in the MADT. */
+    acpi_table_parse_madt(ACPI_MADT_TYPE_INTERRUPT_OVERRIDE,
+                          acpi_count_intr_ovr, UINT_MAX);
+
+    /* Count number of NMI sources in the MADT. */
+    acpi_table_parse_madt(ACPI_MADT_TYPE_NMI_SOURCE, acpi_count_nmi_src,
+                          UINT_MAX);
+
+    max_vcpus = dom0_max_vcpus();
+    /* Calculate the size of the crafted MADT. */
+    size = sizeof(*madt);
+    /*
+     * FIXME: the current vIO-APIC code just supports one IO-APIC instance
+     * per domain. This must be fixed in order to provide the same amount of
+     * IO APICs as available on bare metal.
+     */
+    size += sizeof(*io_apic);
+    size += sizeof(*intsrcovr) * acpi_intr_overrides;
+    size += sizeof(*nmisrc) * acpi_nmi_sources;
+    size += sizeof(*x2apic) * max_vcpus;
+
+    madt = xzalloc_bytes(size);
+    if ( !madt )
+    {
+        printk("Unable to allocate memory for MADT table\n");
+        return -ENOMEM;
+    }
+
+    /* Copy the native MADT table header. */
+    status = acpi_get_table(ACPI_SIG_MADT, 0, &table);
+    if ( !ACPI_SUCCESS(status) )
+    {
+        printk("Failed to get MADT ACPI table, aborting.\n");
+        return -EINVAL;
+    }
+    madt->header = *table;
+    madt->address = APIC_DEFAULT_PHYS_BASE;
+    /*
+     * NB: this is currently set to 4, which is the revision in the ACPI
+     * spec 6.1. Sadly ACPICA doesn't provide revision numbers for the
+     * tables described in the headers.
+     */
+    madt->header.revision = min_t(unsigned char, table->revision, 4);
+
+    /*
+     * Setup the IO APIC entry.
+     * FIXME: the current vIO-APIC code just supports one IO-APIC instance
+     * per domain. This must be fixed in order to provide the same amount of
+     * IO APICs as available on bare metal, and with the same IDs as found in
+     * the native IO APIC MADT entries.
+     */
+    if ( nr_ioapics > 1 )
+        printk("WARNING: found %d IO APICs, Dom0 will only have access to 1 
emulated IO APIC\n",
+               nr_ioapics);
+    io_apic = (void *)(madt + 1);
+    io_apic->header.type = ACPI_MADT_TYPE_IO_APIC;
+    io_apic->header.length = sizeof(*io_apic);
+    io_apic->id = domain_vioapic(d)->id;
+    io_apic->address = VIOAPIC_DEFAULT_BASE_ADDRESS;
+
+    x2apic = (void *)(io_apic + 1);
+    for ( i = 0; i < max_vcpus; i++ )
+    {
+        x2apic->header.type = ACPI_MADT_TYPE_LOCAL_X2APIC;
+        x2apic->header.length = sizeof(*x2apic);
+        x2apic->uid = i;
+        x2apic->local_apic_id = i * 2;
+        x2apic->lapic_flags = ACPI_MADT_ENABLED;
+        x2apic++;
+    }
+
+    /* Setup interrupt overrides. */
+    intsrcovr = (void *)x2apic;
+    acpi_table_parse_madt(ACPI_MADT_TYPE_INTERRUPT_OVERRIDE, acpi_set_intr_ovr,
+                          acpi_intr_overrides);
+
+    /* Setup NMI sources. */
+    nmisrc = (void *)intsrcovr;
+    acpi_table_parse_madt(ACPI_MADT_TYPE_NMI_SOURCE, acpi_set_nmi_src,
+                          acpi_nmi_sources);
+
+    ASSERT(((void *)nmisrc - (void *)madt) == size);
+    madt->header.length = size;
+    /*
+     * Calling acpi_tb_checksum here is a layering violation, but
+     * introducing a wrapper for such simple usage seems overkill.
+     */
+    madt->header.checksum -= acpi_tb_checksum(ACPI_CAST_PTR(u8, madt), size);
+
+    /* Place the new MADT in guest memory space. */
+    if ( pvh_steal_ram(d, size, 0, GB(4), addr) )
+    {
+        printk("Unable to find allocate guest RAM for MADT\n");
+        return -ENOMEM;
+    }
+
+    /* Mark this region as E820_ACPI. */
+    if ( pvh_add_mem_range(d, *addr, *addr + size, E820_ACPI) )
+        printk("Unable to add MADT region to memory map\n");
+
+    rc = hvm_copy_to_guest_phys(*addr, madt, size, d->vcpu[0]);
+    if ( rc )
+    {
+        printk("Unable to copy MADT into guest memory\n");
+        return rc;
+    }
+    xfree(madt);
+
+    return 0;
+}
+
+static bool __init acpi_memory_banned(unsigned long address,
+                                      unsigned long size)
+{
+    unsigned long mfn, nr_pages, i;
+
+    mfn = PFN_DOWN(address);
+    nr_pages = PFN_UP((address & ~PAGE_MASK) + size);
+    for ( i = 0 ; i < nr_pages; i++ )
+        if ( !page_is_ram_type(mfn + i, RAM_TYPE_RESERVED) &&
+             !page_is_ram_type(mfn + i, RAM_TYPE_ACPI) )
+            return true;
+
+    return false;
+}
+
+static bool __init pvh_acpi_table_allowed(const char *sig)
+{
+    static const char __initconst banned_tables[][ACPI_NAME_SIZE] = {
+        ACPI_SIG_HPET, ACPI_SIG_SLIT, ACPI_SIG_SRAT, ACPI_SIG_MPST,
+        ACPI_SIG_PMTT, ACPI_SIG_MADT, ACPI_SIG_DMAR};
+    unsigned int i;
+
+    for ( i = 0 ; i < ARRAY_SIZE(banned_tables); i++ )
+        if ( strncmp(sig, banned_tables[i], ACPI_NAME_SIZE) == 0 )
+            return false;
+
+    /* Make sure table doesn't reside in a RAM region. */
+    if ( acpi_memory_banned(acpi_gbl_root_table_list.tables[i].address,
+                            acpi_gbl_root_table_list.tables[i].length) )
+    {
+        printk("Skipping table %.4s because resides in a non-ACPI, 
non-reserved region\n",
+               sig);
+        return false;
+    }
+
+    return true;
+}
+
+static int __init pvh_setup_acpi_xsdt(struct domain *d, paddr_t madt_addr,
+                                      paddr_t *addr)
+{
+    struct acpi_table_xsdt *xsdt;
+    struct acpi_table_header *table;
+    struct acpi_table_rsdp *rsdp;
+    unsigned long size = sizeof(*xsdt);
+    unsigned int i, j, num_tables = 0;
+    paddr_t xsdt_paddr;
+    int rc;
+
+    /*
+     * Restore original DMAR table signature, we are going to filter it from
+     * the new XSDT that is presented to the guest, so it is no longer
+     * necessary to have it's signature zapped.
+     */
+    acpi_dmar_reinstate();
+
+    /* Count the number of tables that will be added to the XSDT. */
+    for( i = 0; i < acpi_gbl_root_table_list.count; i++ )
+    {
+        const char *sig = acpi_gbl_root_table_list.tables[i].signature.ascii;
+
+        if ( pvh_acpi_table_allowed(sig) )
+            num_tables++;
+    }
+
+    /*
+     * No need to add or subtract anything because struct acpi_table_xsdt
+     * includes one array slot already, and we have filtered out the original
+     * MADT and we are going to add a custom built MADT.
+     */
+    size += num_tables * sizeof(xsdt->table_offset_entry[0]);
+
+    xsdt = xzalloc_bytes(size);
+    if ( !xsdt )
+    {
+        printk("Unable to allocate memory for XSDT table\n");
+        return -ENOMEM;
+    }
+
+    /* Copy the native XSDT table header. */
+    rsdp = acpi_os_map_memory(acpi_os_get_root_pointer(), sizeof(*rsdp));
+    if ( !rsdp )
+    {
+        printk("Unable to map RSDP\n");
+        return -EINVAL;
+    }
+    xsdt_paddr = rsdp->xsdt_physical_address;
+    acpi_os_unmap_memory(rsdp, sizeof(*rsdp));
+    table = acpi_os_map_memory(xsdt_paddr, sizeof(*table));
+    if ( !table )
+    {
+        printk("Unable to map XSDT\n");
+        return -EINVAL;
+    }
+    xsdt->header = *table;
+    acpi_os_unmap_memory(table, sizeof(*table));
+
+    /* Add the custom MADT. */
+    xsdt->table_offset_entry[0] = madt_addr;
+
+    /* Copy the addresses of the rest of the allowed tables. */
+    for( i = 0, j = 1; i < acpi_gbl_root_table_list.count; i++ )
+    {
+        const char *sig = acpi_gbl_root_table_list.tables[i].signature.ascii;
+
+        if ( pvh_acpi_table_allowed(sig) )
+            xsdt->table_offset_entry[j++] =
+                                acpi_gbl_root_table_list.tables[i].address;
+    }
+
+    xsdt->header.revision = 1;
+    xsdt->header.length = size;
+    /*
+     * Calling acpi_tb_checksum here is a layering violation, but
+     * introducing a wrapper for such simple usage seems overkill.
+     */
+    xsdt->header.checksum -= acpi_tb_checksum(ACPI_CAST_PTR(u8, xsdt), size);
+
+    /* Place the new XSDT in guest memory space. */
+    if ( pvh_steal_ram(d, size, 0, GB(4), addr) )
+    {
+        printk("Unable to find guest RAM for XSDT\n");
+        return -ENOMEM;
+    }
+
+    /* Mark this region as E820_ACPI. */
+    if ( pvh_add_mem_range(d, *addr, *addr + size, E820_ACPI) )
+        printk("Unable to add XSDT region to memory map\n");
+
+    rc = hvm_copy_to_guest_phys(*addr, xsdt, size, d->vcpu[0]);
+    if ( rc )
+    {
+        printk("Unable to copy XSDT into guest memory\n");
+        return rc;
+    }
+    xfree(xsdt);
+
+    return 0;
+}
+
+static int __init pvh_setup_acpi(struct domain *d, paddr_t start_info)
+{
+    unsigned long pfn, nr_pages;
+    paddr_t madt_paddr, xsdt_paddr, rsdp_paddr;
+    unsigned int i;
+    int rc;
+    struct acpi_table_rsdp *native_rsdp, rsdp = {
+        .signature = ACPI_SIG_RSDP,
+        .revision = 2,
+        .length = sizeof(rsdp),
+    };
+
+
+    /* Scan top-level tables and add their regions to the guest memory map. */
+    for( i = 0; i < acpi_gbl_root_table_list.count; i++ )
+    {
+        const char *sig = acpi_gbl_root_table_list.tables[i].signature.ascii;
+        unsigned long addr = acpi_gbl_root_table_list.tables[i].address;
+        unsigned long size = acpi_gbl_root_table_list.tables[i].length;
+
+        /*
+         * Make sure the original MADT is also mapped, so that Dom0 can
+         * properly access the data returned by _MAT methods in case it's
+         * re-using MADT memory.
+         */
+        if ( strncmp(sig, ACPI_SIG_MADT, ACPI_NAME_SIZE)
+             ? pvh_acpi_table_allowed(sig)
+             : !acpi_memory_banned(addr, size) )
+             pvh_add_mem_range(d, addr, addr + size, E820_ACPI);
+    }
+
+    /* Identity map ACPI e820 regions. */
+    for ( i = 0; i < d->arch.nr_e820; i++ )
+    {
+        if ( d->arch.e820[i].type != E820_ACPI &&
+             d->arch.e820[i].type != E820_NVS )
+            continue;
+
+        pfn = PFN_DOWN(d->arch.e820[i].addr);
+        nr_pages = PFN_UP((d->arch.e820[i].addr & ~PAGE_MASK) +
+                          d->arch.e820[i].size);
+
+        rc = modify_identity_mmio(d, pfn, nr_pages, true);
+        if ( rc )
+        {
+            printk("Failed to map ACPI region [%#lx, %#lx) into Dom0 memory 
map\n",
+                   pfn, pfn + nr_pages);
+            return rc;
+        }
+    }
+
+    rc = pvh_setup_acpi_madt(d, &madt_paddr);
+    if ( rc )
+        return rc;
+
+    rc = pvh_setup_acpi_xsdt(d, madt_paddr, &xsdt_paddr);
+    if ( rc )
+        return rc;
+
+    /* Craft a custom RSDP. */
+    native_rsdp = acpi_os_map_memory(acpi_os_get_root_pointer(), sizeof(rsdp));
+    memcpy(rsdp.oem_id, native_rsdp->oem_id, sizeof(rsdp.oem_id));
+    acpi_os_unmap_memory(native_rsdp, sizeof(rsdp));
+    rsdp.xsdt_physical_address = xsdt_paddr;
+    /*
+     * Calling acpi_tb_checksum here is a layering violation, but
+     * introducing a wrapper for such simple usage seems overkill.
+     */
+    rsdp.checksum -= acpi_tb_checksum(ACPI_CAST_PTR(u8, &rsdp),
+                                      ACPI_RSDP_REV0_SIZE);
+    rsdp.extended_checksum -= acpi_tb_checksum(ACPI_CAST_PTR(u8, &rsdp),
+                                               sizeof(rsdp));
+
+    /*
+     * Place the new RSDP in guest memory space.
+     *
+     * NB: this RSDP is not going to replace the original RSDP, which should
+     * still be accessible to the guest. However that RSDP is going to point to
+     * the native RSDT, and should not be used for the Dom0 kernel's boot
+     * purposes (we keep it visible for post boot access).
+     */
+    if ( pvh_steal_ram(d, sizeof(rsdp), 0, GB(4), &rsdp_paddr) )
+    {
+        printk("Unable to allocate guest RAM for RSDP\n");
+        return -ENOMEM;
+    }
+
+    /* Mark this region as E820_ACPI. */
+    if ( pvh_add_mem_range(d, rsdp_paddr, rsdp_paddr + sizeof(rsdp),
+                           E820_ACPI) )
+        printk("Unable to add RSDP region to memory map\n");
+
+    /* Copy RSDP into guest memory. */
+    rc = hvm_copy_to_guest_phys(rsdp_paddr, &rsdp, sizeof(rsdp), d->vcpu[0]);
+    if ( rc )
+    {
+        printk("Unable to copy RSDP into guest memory\n");
+        return rc;
+    }
+
+    /* Copy RSDP address to start_info. */
+    rc = hvm_copy_to_guest_phys(start_info +
+                                offsetof(struct hvm_start_info, rsdp_paddr),
+                                &rsdp_paddr,
+                                sizeof(((struct hvm_start_info *)
+                                        0)->rsdp_paddr),
+                                d->vcpu[0]);
+    if ( rc )
+    {
+        printk("Unable to copy RSDP into guest memory\n");
+        return rc;
+    }
+
+    return 0;
+}
+
 static int __init construct_dom0_pvh(struct domain *d, const module_t *image,
                                      unsigned long image_headroom,
                                      module_t *initrd,
@@ -2231,6 +2658,13 @@ static int __init construct_dom0_pvh(struct domain *d, 
const module_t *image,
         return rc;
     }
 
+    rc = pvh_setup_acpi(d, start_info);
+    if ( rc )
+    {
+        printk("Failed to setup Dom0 ACPI tables: %d\n", rc);
+        return rc;
+    }
+
     panic("Building a PVHv2 Dom0 is not yet supported.");
     return 0;
 }
-- 
2.10.1 (Apple Git-78)


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