The following commit has been merged into the x86/seves branch of tip: Commit-ID: 885689e47dfa1499b756a07237eb645234d93cf9 Gitweb: https://git.kernel.org/tip/885689e47dfa1499b756a07237eb645234d93cf9 Author: Tom Lendacky <thomas.lendacky@xxxxxxx> AuthorDate: Mon, 07 Sep 2020 15:15:42 +02:00 Committer: Borislav Petkov <bp@xxxxxxx> CommitterDate: Wed, 09 Sep 2020 11:33:19 +02:00 x86/sev-es: Setup per-CPU GHCBs for the runtime handler The runtime handler needs one GHCB per-CPU. Set them up and map them unencrypted. [ bp: Touchups and simplification. ] Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx> Signed-off-by: Joerg Roedel <jroedel@xxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Link: https://lkml.kernel.org/r/20200907131613.12703-42-joro@xxxxxxxxxx --- arch/x86/include/asm/mem_encrypt.h | 2 +- arch/x86/kernel/sev-es.c | 56 ++++++++++++++++++++++++++++- arch/x86/kernel/traps.c | 3 ++- 3 files changed, 60 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h index 4e72b73..c9f5df0 100644 --- a/arch/x86/include/asm/mem_encrypt.h +++ b/arch/x86/include/asm/mem_encrypt.h @@ -49,6 +49,7 @@ void __init mem_encrypt_free_decrypted_mem(void); /* Architecture __weak replacement functions */ void __init mem_encrypt_init(void); +void __init sev_es_init_vc_handling(void); bool sme_active(void); bool sev_active(void); bool sev_es_active(void); @@ -72,6 +73,7 @@ static inline void __init sme_early_init(void) { } static inline void __init sme_encrypt_kernel(struct boot_params *bp) { } static inline void __init sme_enable(struct boot_params *bp) { } +static inline void sev_es_init_vc_handling(void) { } static inline bool sme_active(void) { return false; } static inline bool sev_active(void) { return false; } static inline bool sev_es_active(void) { return false; } diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index 213a427..720b1b6 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -8,8 +8,13 @@ */ #include <linux/sched/debug.h> /* For show_regs() */ -#include <linux/kernel.h> +#include <linux/percpu-defs.h> +#include <linux/mem_encrypt.h> #include <linux/printk.h> +#include <linux/mm_types.h> +#include <linux/set_memory.h> +#include <linux/memblock.h> +#include <linux/kernel.h> #include <linux/mm.h> #include <asm/sev-es.h> @@ -29,6 +34,13 @@ static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE); */ static struct ghcb __initdata *boot_ghcb; +/* #VC handler runtime per-CPU data */ +struct sev_es_runtime_data { + struct ghcb ghcb_page; +}; + +static DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data); + /* Needed in vc_early_forward_exception */ void do_early_exception(struct pt_regs *regs, int trapnr); @@ -198,6 +210,48 @@ static bool __init sev_es_setup_ghcb(void) return true; } +static void __init alloc_runtime_data(int cpu) +{ + struct sev_es_runtime_data *data; + + data = memblock_alloc(sizeof(*data), PAGE_SIZE); + if (!data) + panic("Can't allocate SEV-ES runtime data"); + + per_cpu(runtime_data, cpu) = data; +} + +static void __init init_ghcb(int cpu) +{ + struct sev_es_runtime_data *data; + int err; + + data = per_cpu(runtime_data, cpu); + + err = early_set_memory_decrypted((unsigned long)&data->ghcb_page, + sizeof(data->ghcb_page)); + if (err) + panic("Can't map GHCBs unencrypted"); + + memset(&data->ghcb_page, 0, sizeof(data->ghcb_page)); +} + +void __init sev_es_init_vc_handling(void) +{ + int cpu; + + BUILD_BUG_ON(offsetof(struct sev_es_runtime_data, ghcb_page) % PAGE_SIZE); + + if (!sev_es_active()) + return; + + /* Initialize per-cpu GHCB pages */ + for_each_possible_cpu(cpu) { + alloc_runtime_data(cpu); + init_ghcb(cpu); + } +} + static void __init vc_early_forward_exception(struct es_em_ctxt *ctxt) { int trapnr = ctxt->fi.vector; diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 81a2fb7..2dc32b0 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -1074,6 +1074,9 @@ void __init trap_init(void) /* Init cpu_entry_area before IST entries are set up */ setup_cpu_entry_areas(); + /* Init GHCB memory pages when running as an SEV-ES guest */ + sev_es_init_vc_handling(); + idt_setup_traps(); /*
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