Date: Thu, 30 Jun 2022 06:54:21 GMT From: =?utf-8?Q?Roger=20Pau=20Monn=C3=A9?= <royger@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 77cb05db0cee - main - x86/xen: stop assuming kernel memory loading order in PVH Message-ID: <202206300654.25U6sLSs056495@gitrepo.freebsd.org>
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The branch main has been updated by royger: URL: https://cgit.FreeBSD.org/src/commit/?id=77cb05db0cee0b052cc1a75da0741eb404eed473 commit 77cb05db0cee0b052cc1a75da0741eb404eed473 Author: Roger Pau Monné <royger@FreeBSD.org> AuthorDate: 2022-06-28 15:37:00 +0000 Commit: Roger Pau Monné <royger@FreeBSD.org> CommitDate: 2022-06-30 06:53:16 +0000 x86/xen: stop assuming kernel memory loading order in PVH Do not assume that start_info will always be loaded at the highest memory address, and instead check the position of all the loaded elements in order to find the last loaded one, and thus a likely safe place to use as early boot allocation memory space. Reported by: markj, cperciva Sponsored by: Citrix Systems R&D Reviewed by: markj Differential revision: https://reviews.freebsd.org/D35628 --- sys/x86/xen/pv.c | 52 ++++++++++++++++++++++++++++++---------------------- 1 file changed, 30 insertions(+), 22 deletions(-) diff --git a/sys/x86/xen/pv.c b/sys/x86/xen/pv.c index c5d7629d0bc5..796b3ca844de 100644 --- a/sys/x86/xen/pv.c +++ b/sys/x86/xen/pv.c @@ -68,6 +68,7 @@ __FBSDID("$FreeBSD$"); #include <machine/intr_machdep.h> #include <machine/md_var.h> #include <machine/metadata.h> +#include <machine/cpu.h> #include <xen/xen-os.h> #include <xen/hvm.h> @@ -143,10 +144,36 @@ hammer_time_xen(vm_paddr_t start_info_paddr) } /* - * The hvm_start_into structure is always appended after loading - * the kernel and modules. + * Select the higher address to use as physfree: either after + * start_info, after the kernel, after the memory map or after any of + * the modules. We assume enough memory to be available after the + * selected address for the needs of very early memory allocations. */ - physfree = roundup2(start_info_paddr + PAGE_SIZE, PAGE_SIZE); + physfree = roundup2(start_info_paddr + sizeof(struct hvm_start_info), + PAGE_SIZE); + physfree = MAX(roundup2((vm_paddr_t)_end - KERNBASE, PAGE_SIZE), + physfree); + + if (start_info->memmap_paddr != 0) + physfree = MAX(roundup2(start_info->memmap_paddr + + start_info->memmap_entries * + sizeof(struct hvm_memmap_table_entry), PAGE_SIZE), + physfree); + + if (start_info->modlist_paddr != 0) { + unsigned int i; + + if (start_info->nr_modules == 0) { + xc_printf( + "ERROR: modlist_paddr != 0 but nr_modules == 0\n"); + HYPERVISOR_shutdown(SHUTDOWN_crash); + } + mod = (struct hvm_modlist_entry *) + (start_info->modlist_paddr + KERNBASE); + for (i = 0; i < start_info->nr_modules; i++) + physfree = MAX(roundup2(mod[i].paddr + mod[i].size, + PAGE_SIZE), physfree); + } xatp.domid = DOMID_SELF; xatp.idx = 0; @@ -168,25 +195,6 @@ hammer_time_xen(vm_paddr_t start_info_paddr) bzero_early(kenv, PAGE_SIZE); init_static_kenv(kenv, PAGE_SIZE); - if (start_info->modlist_paddr != 0) { - if (start_info->modlist_paddr >= physfree) { - xc_printf( - "ERROR: unexpected module list memory address\n"); - HYPERVISOR_shutdown(SHUTDOWN_crash); - } - if (start_info->nr_modules == 0) { - xc_printf( - "ERROR: modlist_paddr != 0 but nr_modules == 0\n"); - HYPERVISOR_shutdown(SHUTDOWN_crash); - } - mod = (struct hvm_modlist_entry *) - (start_info->modlist_paddr + KERNBASE); - if (mod[0].paddr >= physfree) { - xc_printf("ERROR: unexpected module memory address\n"); - HYPERVISOR_shutdown(SHUTDOWN_crash); - } - } - /* Set the hooks for early functions that diverge from bare metal */ init_ops = xen_pvh_init_ops; hvm_start_flags = start_info->flags;
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