[PATCH 06/12] x86/sev: Cache AP Jump Table Address
From: Joerg Roedel <joro@8bytes.org>
Date: 2021-07-21 14:21:13
Also in:
linux-coco, lkml, virtualization
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Joerg Roedel <redacted> Store the physical address of the AP Jump Table in kernel memory so that it does not need to be fetched from the Hypervisor again. Signed-off-by: Joerg Roedel <redacted> --- arch/x86/kernel/sev.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 5d3422e8b25e..eedba56b6bac 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c@@ -42,6 +42,9 @@ static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE); */ static struct ghcb __initdata *boot_ghcb; +/* Cached AP Jump Table Address */ +static phys_addr_t sev_es_jump_table_pa; + /* #VC handler runtime per-CPU data */ struct sev_es_runtime_data { struct ghcb ghcb_page;
@@ -546,12 +549,14 @@ void noinstr __sev_es_nmi_complete(void) __sev_put_ghcb(&state); } -static u64 get_jump_table_addr(void) +static phys_addr_t get_jump_table_addr(void) { struct ghcb_state state; unsigned long flags; struct ghcb *ghcb; - u64 ret = 0; + + if (sev_es_jump_table_pa) + return sev_es_jump_table_pa; local_irq_save(flags);
@@ -567,39 +572,36 @@ static u64 get_jump_table_addr(void) if (ghcb_sw_exit_info_1_is_valid(ghcb) && ghcb_sw_exit_info_2_is_valid(ghcb)) - ret = ghcb->save.sw_exit_info_2; + sev_es_jump_table_pa = (phys_addr_t)ghcb->save.sw_exit_info_2; __sev_put_ghcb(&state); local_irq_restore(flags); - return ret; + return sev_es_jump_table_pa; } int sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { u16 startup_cs, startup_ip; - phys_addr_t jump_table_pa; - u64 jump_table_addr; u16 __iomem *jump_table; + phys_addr_t pa; - jump_table_addr = get_jump_table_addr(); + pa = get_jump_table_addr(); /* On UP guests there is no jump table so this is not a failure */ - if (!jump_table_addr) + if (!pa) return 0; /* Check if AP Jump Table is page-aligned */ - if (jump_table_addr & ~PAGE_MASK) + if (pa & ~PAGE_MASK) return -EINVAL; - jump_table_pa = jump_table_addr & PAGE_MASK; - startup_cs = (u16)(rmh->trampoline_start >> 4); startup_ip = (u16)(rmh->sev_es_trampoline_start - rmh->trampoline_start); - jump_table = ioremap_encrypted(jump_table_pa, PAGE_SIZE); + jump_table = ioremap_encrypted(pa, PAGE_SIZE); if (!jump_table) return -EIO;
--
2.31.1