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Date: Fri, 13 Dec 2013 12:55:26 -0500
From: Boris Ostrovsky <boris.ostrovsky@...cle.com>
To: Konrad Rzeszutek Wilk <konrad@...nel.org>
CC: xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org,
george.dunlap@...citrix.com, ian.jackson@...citrix.com,
mukesh.rathor@...cle.com, tim@....org, jbeulich@...e.com,
david.vrabel@...rix.com,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Subject: Re: [PATCH V10 04/14] xen/pvh: bootup and setup (E820) related changes.
On 12/12/2013 09:10 PM, Konrad Rzeszutek Wilk wrote:
> From: Mukesh Rathor <mukesh.rathor@...cle.com>
>
> In the bootup code for PVH we can trap cpuid via vmexit, so don't
> need to use emulated prefix call. We also check for vector callback
> early on, as it is a required feature. PVH also runs at default kernel
> IOPL.
>
> In setup.c which deals with E820, in xen_add_extra_mem() we can skip
> updating P2M as it's managed by Xen. PVH maps the entire IO space,
> but only RAM pages need to be repopulated.
>
> Finally, pure PV settings are moved to a separate function that are
> only called for pure PV, ie, pv with pvmmu.
>
> Signed-off-by: Mukesh Rathor <mukesh.rathor@...cle.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> [ ijc -- rebase onto xen PVonHVM: use E820_Reserved area for
> shared_info ]
> [v2: Rebase on v3.9-rc1 with MMIO/Kexec reverted]
>
> Conflicts:
> arch/x86/xen/setup.c
> [due to "xen: Support 64-bit PV guest receiving NMIs"]
> ---
> arch/x86/xen/enlighten.c | 77 ++++++++++++++++++++++++++++++++++-----------
> arch/x86/xen/setup.c | 63 ++++++++++++++++++++++++++++++-------
> 2 files changed, 109 insertions(+), 31 deletions(-)
>
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index fa6ade7..500508d 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -46,6 +46,7 @@
> #include <xen/hvm.h>
> #include <xen/hvc-console.h>
> #include <xen/acpi.h>
> +#include <xen/features.h>
>
> #include <asm/paravirt.h>
> #include <asm/apic.h>
> @@ -129,6 +130,9 @@ RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
> __read_mostly int xen_have_vector_callback;
> EXPORT_SYMBOL_GPL(xen_have_vector_callback);
>
> +#define xen_pvh_domain() (xen_pv_domain() && \
> + xen_feature(XENFEAT_auto_translated_physmap) && \
> + xen_have_vector_callback)
Can this be used in earlier patches instead of checking for
XENFEAT_auto_translated_physmap, when it's clear that we actually mean PVH?
> /*
> * Point at some empty memory to start with. We map the real shared_info
> * page as soon as fixmap is up and running.
> @@ -262,8 +266,9 @@ static void __init xen_banner(void)
> struct xen_extraversion extra;
> HYPERVISOR_xen_version(XENVER_extraversion, &extra);
>
> - printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
> - pv_info.name);
> + pr_info("Booting paravirtualized kernel %son %s\n",
> + xen_feature(XENFEAT_auto_translated_physmap) ?
... and here as well (and possibly elsewhere).
> + "with PVH extensions " : "", pv_info.name);
> printk(KERN_INFO "Xen version: %d.%d%s%s\n",
> version >> 16, version & 0xffff, extra.extraversion,
> xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
> @@ -331,12 +336,15 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
> break;
> }
>
> - asm(XEN_EMULATE_PREFIX "cpuid"
> - : "=a" (*ax),
> - "=b" (*bx),
> - "=c" (*cx),
> - "=d" (*dx)
> - : "0" (*ax), "2" (*cx));
> + if (xen_pvh_domain())
> + native_cpuid(ax, bx, cx, dx);
> + else
> + asm(XEN_EMULATE_PREFIX "cpuid"
> + : "=a" (*ax),
> + "=b" (*bx),
> + "=c" (*cx),
> + "=d" (*dx)
> + : "0" (*ax), "2" (*cx));
>
> *bx &= maskebx;
> *cx &= maskecx;
> @@ -1125,6 +1133,10 @@ void xen_setup_shared_info(void)
> HYPERVISOR_shared_info =
> (struct shared_info *)__va(xen_start_info->shared_info);
>
> + /* PVH TBD/FIXME: vcpu info placement in phase 2 */
> + if (xen_pvh_domain())
> + return;
> +
> #ifndef CONFIG_SMP
> /* In UP this is as good a place as any to set up shared info */
> xen_setup_vcpu_info_placement();
> @@ -1410,6 +1422,11 @@ static void __init xen_boot_params_init_edd(void)
> */
> static void __init xen_setup_stackprotector(void)
> {
> + /* PVH TBD/FIXME: investigate setup_stack_canary_segment */
setup_stack_canary_segment() is for 32-bit only and since PVH (which I
assume is what this 'if' is about) is a 64-bit only binary this call is
a nop.
> + if (xen_feature(XENFEAT_auto_translated_physmap)) {
> + switch_to_new_gdt(0);
> + return;
> + }
> pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot;
> pv_cpu_ops.load_gdt = xen_load_gdt_boot;
>
> @@ -1420,6 +1437,19 @@ static void __init xen_setup_stackprotector(void)
> pv_cpu_ops.load_gdt = xen_load_gdt;
> }
>
> +static void __init xen_pvh_early_guest_init(void)
> +{
> + if (xen_feature(XENFEAT_hvm_callback_vector))
> + xen_have_vector_callback = 1;
> +
> +#ifdef CONFIG_X86_32
> + if (xen_feature(XENFEAT_auto_translated_physmap)) {
> + xen_raw_printk("ERROR: 32bit PVH guests are not supported\n");
> + BUG();
> + }
> +#endif
> +}
> +
> /* First C function to be called on Xen boot */
> asmlinkage void __init xen_start_kernel(void)
> {
> @@ -1431,13 +1461,18 @@ asmlinkage void __init xen_start_kernel(void)
>
> xen_domain_type = XEN_PV_DOMAIN;
>
> + xen_setup_features();
> + xen_pvh_early_guest_init();
> xen_setup_machphys_mapping();
>
> /* Install Xen paravirt ops */
> pv_info = xen_info;
> pv_init_ops = xen_init_ops;
> - pv_cpu_ops = xen_cpu_ops;
> pv_apic_ops = xen_apic_ops;
> + if (xen_pvh_domain())
> + pv_cpu_ops.cpuid = xen_cpuid;
> + else
> + pv_cpu_ops = xen_cpu_ops;
>
> x86_init.resources.memory_setup = xen_memory_setup;
> x86_init.oem.arch_setup = xen_arch_setup;
> @@ -1469,8 +1504,6 @@ asmlinkage void __init xen_start_kernel(void)
> /* Work out if we support NX */
> x86_configure_nx();
>
> - xen_setup_features();
> -
> /* Get mfn list */
> if (!xen_feature(XENFEAT_auto_translated_physmap))
> xen_build_dynamic_phys_to_machine();
> @@ -1548,14 +1581,18 @@ asmlinkage void __init xen_start_kernel(void)
> /* set the limit of our address space */
> xen_reserve_top();
>
> - /* We used to do this in xen_arch_setup, but that is too late on AMD
> - * were early_cpu_init (run before ->arch_setup()) calls early_amd_init
> - * which pokes 0xcf8 port.
> - */
> - set_iopl.iopl = 1;
> - rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
> - if (rc != 0)
> - xen_raw_printk("physdev_op failed %d\n", rc);
> + /* PVH: runs at default kernel iopl of 0 */
> + if (!xen_pvh_domain()) {
> + /*
> + * We used to do this in xen_arch_setup, but that is too late
> + * on AMD were early_cpu_init (run before ->arch_setup()) calls
> + * early_amd_init which pokes 0xcf8 port.
> + */
> + set_iopl.iopl = 1;
> + rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
> + if (rc != 0)
> + xen_raw_printk("physdev_op failed %d\n", rc);
> + }
>
> #ifdef CONFIG_X86_32
> /* set up basic CPUID stuff */
> @@ -1625,6 +1662,8 @@ asmlinkage void __init xen_start_kernel(void)
> }
>
> void __ref xen_hvm_init_shared_info(void)
> +/* Use a pfn in RAM, may move to MMIO before kexec.
> + * This function also called for PVH dom0 */
> {
> int cpu;
> struct xen_add_to_physmap xatp;
> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> index 68c054f..e3dcd8c 100644
> --- a/arch/x86/xen/setup.c
> +++ b/arch/x86/xen/setup.c
> @@ -27,6 +27,7 @@
> #include <xen/interface/memory.h>
> #include <xen/interface/physdev.h>
> #include <xen/features.h>
> +#include "mmu.h"
> #include "xen-ops.h"
> #include "vdso.h"
>
> @@ -81,6 +82,9 @@ static void __init xen_add_extra_mem(u64 start, u64 size)
>
> memblock_reserve(start, size);
>
> + if (xen_feature(XENFEAT_auto_translated_physmap))
> + return;
> +
> xen_max_p2m_pfn = PFN_DOWN(start + size);
> for (pfn = PFN_DOWN(start); pfn < xen_max_p2m_pfn; pfn++) {
> unsigned long mfn = pfn_to_mfn(pfn);
> @@ -103,6 +107,7 @@ static unsigned long __init xen_do_chunk(unsigned long start,
> .domid = DOMID_SELF
> };
> unsigned long len = 0;
> + int xlated_phys = xen_feature(XENFEAT_auto_translated_physmap);
This is inconsistent with other uses of
xen_feature(XENFEAT_auto_translated_physmap), so far xen_feature() has
always been used.
> unsigned long pfn;
> int ret;
>
> @@ -116,7 +121,7 @@ static unsigned long __init xen_do_chunk(unsigned long start,
> continue;
> frame = mfn;
> } else {
> - if (mfn != INVALID_P2M_ENTRY)
> + if (!xlated_phys && mfn != INVALID_P2M_ENTRY)
> continue;
> frame = pfn;
> }
> @@ -239,6 +244,27 @@ static void __init xen_set_identity_and_release_chunk(
> *identity += set_phys_range_identity(start_pfn, end_pfn);
> }
>
> +/* For PVH, the pfns [0..MAX] are mapped to mfn's in the EPT/NPT. The mfns
> + * are released as part of this 1:1 mapping hypercall back to the dom heap.
> + * Also, we map the entire IO space, ie, beyond max_pfn_mapped.
> + */
> +static void __init xen_pvh_identity_map_chunk(unsigned long start_pfn,
> + unsigned long end_pfn, unsigned long *released,
> + unsigned long *identity, unsigned long max_pfn)
> +{
> + unsigned long pfn;
> + int numpfns = 1, add_mapping = 1;
No need for these two variables;
> +
> + for (pfn = start_pfn; pfn < end_pfn; pfn++)
> + xen_set_clr_mmio_pvh_pte(pfn, pfn, numpfns, add_mapping);
> +
> + if (start_pfn <= max_pfn) {
> + unsigned long end = min(max_pfn_mapped, end_pfn);
> + *released += end - start_pfn;
> + }
> + *identity += end_pfn - start_pfn;
> +}
> +
> static unsigned long __init xen_set_identity_and_release(
> const struct e820entry *list, size_t map_size, unsigned long nr_pages)
> {
> @@ -247,6 +273,7 @@ static unsigned long __init xen_set_identity_and_release(
> unsigned long identity = 0;
> const struct e820entry *entry;
> int i;
> + int xlated_phys = xen_feature(XENFEAT_auto_translated_physmap);
Again xlated_phys.
-boris
>
> /*
> * Combine non-RAM regions and gaps until a RAM region (or the
> @@ -268,11 +295,17 @@ static unsigned long __init xen_set_identity_and_release(
> if (entry->type == E820_RAM)
> end_pfn = PFN_UP(entry->addr);
>
> - if (start_pfn < end_pfn)
> - xen_set_identity_and_release_chunk(
> - start_pfn, end_pfn, nr_pages,
> - &released, &identity);
> -
> + if (start_pfn < end_pfn) {
> + if (xlated_phys) {
> + xen_pvh_identity_map_chunk(start_pfn,
> + end_pfn, &released, &identity,
> + nr_pages);
> + } else {
> + xen_set_identity_and_release_chunk(
> + start_pfn, end_pfn, nr_pages,
> + &released, &identity);
> + }
> + }
> start = end;
> }
> }
> @@ -563,16 +596,13 @@ void xen_enable_nmi(void)
> BUG();
> #endif
> }
> -void __init xen_arch_setup(void)
> +void __init xen_pvmmu_arch_setup(void)
> {
> - xen_panic_handler_init();
> -
> HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
> HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
>
> - if (!xen_feature(XENFEAT_auto_translated_physmap))
> - HYPERVISOR_vm_assist(VMASST_CMD_enable,
> - VMASST_TYPE_pae_extended_cr3);
> + HYPERVISOR_vm_assist(VMASST_CMD_enable,
> + VMASST_TYPE_pae_extended_cr3);
>
> if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
> register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
> @@ -581,6 +611,15 @@ void __init xen_arch_setup(void)
> xen_enable_sysenter();
> xen_enable_syscall();
> xen_enable_nmi();
> +}
> +
> +/* This function not called for HVM domain */
> +void __init xen_arch_setup(void)
> +{
> + xen_panic_handler_init();
> +
> + if (!xen_feature(XENFEAT_auto_translated_physmap))
> + xen_pvmmu_arch_setup();
> #ifdef CONFIG_ACPI
> if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
> printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
--
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