[PATCH v2 06/12] x86/sev: Cache AP Jump Table Address

[Joerg Roedel]

From: Joerg Roedel <jroe...@suse.de>

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 <jroe...@suse.de>
---
 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;
 
-- 
2.33.0

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