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Diffstat (limited to 'arch/x86/kernel/sev.c')
-rw-r--r--arch/x86/kernel/sev.c131
1 files changed, 67 insertions, 64 deletions
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index a6895e440bc3..a9fc2ac7a8bd 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -11,7 +11,7 @@
#include <linux/sched/debug.h> /* For show_regs() */
#include <linux/percpu-defs.h>
-#include <linux/mem_encrypt.h>
+#include <linux/cc_platform.h>
#include <linux/printk.h>
#include <linux/mm_types.h>
#include <linux/set_memory.h>
@@ -23,7 +23,7 @@
#include <asm/stacktrace.h>
#include <asm/sev.h>
#include <asm/insn-eval.h>
-#include <asm/fpu/internal.h>
+#include <asm/fpu/xcr.h>
#include <asm/processor.h>
#include <asm/realmode.h>
#include <asm/traps.h>
@@ -46,16 +46,6 @@ static struct ghcb __initdata *boot_ghcb;
struct sev_es_runtime_data {
struct ghcb ghcb_page;
- /* Physical storage for the per-CPU IST stack of the #VC handler */
- char ist_stack[EXCEPTION_STKSZ] __aligned(PAGE_SIZE);
-
- /*
- * Physical storage for the per-CPU fall-back stack of the #VC handler.
- * The fall-back stack is used when it is not safe to switch back to the
- * interrupted stack in the #VC entry code.
- */
- char fallback_stack[EXCEPTION_STKSZ] __aligned(PAGE_SIZE);
-
/*
* Reserve one page per CPU as backup storage for the unencrypted GHCB.
* It is needed when an NMI happens while the #VC handler uses the real
@@ -99,27 +89,6 @@ DEFINE_STATIC_KEY_FALSE(sev_es_enable_key);
/* Needed in vc_early_forward_exception */
void do_early_exception(struct pt_regs *regs, int trapnr);
-static void __init setup_vc_stacks(int cpu)
-{
- struct sev_es_runtime_data *data;
- struct cpu_entry_area *cea;
- unsigned long vaddr;
- phys_addr_t pa;
-
- data = per_cpu(runtime_data, cpu);
- cea = get_cpu_entry_area(cpu);
-
- /* Map #VC IST stack */
- vaddr = CEA_ESTACK_BOT(&cea->estacks, VC);
- pa = __pa(data->ist_stack);
- cea_set_pte((void *)vaddr, pa, PAGE_KERNEL);
-
- /* Map VC fall-back stack */
- vaddr = CEA_ESTACK_BOT(&cea->estacks, VC2);
- pa = __pa(data->fallback_stack);
- cea_set_pte((void *)vaddr, pa, PAGE_KERNEL);
-}
-
static __always_inline bool on_vc_stack(struct pt_regs *regs)
{
unsigned long sp = regs->sp;
@@ -325,11 +294,6 @@ static enum es_result vc_write_mem(struct es_em_ctxt *ctxt,
char *dst, char *buf, size_t size)
{
unsigned long error_code = X86_PF_PROT | X86_PF_WRITE;
- char __user *target = (char __user *)dst;
- u64 d8;
- u32 d4;
- u16 d2;
- u8 d1;
/*
* This function uses __put_user() independent of whether kernel or user
@@ -351,26 +315,42 @@ static enum es_result vc_write_mem(struct es_em_ctxt *ctxt,
* instructions here would cause infinite nesting.
*/
switch (size) {
- case 1:
+ case 1: {
+ u8 d1;
+ u8 __user *target = (u8 __user *)dst;
+
memcpy(&d1, buf, 1);
if (__put_user(d1, target))
goto fault;
break;
- case 2:
+ }
+ case 2: {
+ u16 d2;
+ u16 __user *target = (u16 __user *)dst;
+
memcpy(&d2, buf, 2);
if (__put_user(d2, target))
goto fault;
break;
- case 4:
+ }
+ case 4: {
+ u32 d4;
+ u32 __user *target = (u32 __user *)dst;
+
memcpy(&d4, buf, 4);
if (__put_user(d4, target))
goto fault;
break;
- case 8:
+ }
+ case 8: {
+ u64 d8;
+ u64 __user *target = (u64 __user *)dst;
+
memcpy(&d8, buf, 8);
if (__put_user(d8, target))
goto fault;
break;
+ }
default:
WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size);
return ES_UNSUPPORTED;
@@ -393,11 +373,6 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
char *src, char *buf, size_t size)
{
unsigned long error_code = X86_PF_PROT;
- char __user *s = (char __user *)src;
- u64 d8;
- u32 d4;
- u16 d2;
- u8 d1;
/*
* This function uses __get_user() independent of whether kernel or user
@@ -419,26 +394,41 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
* instructions here would cause infinite nesting.
*/
switch (size) {
- case 1:
+ case 1: {
+ u8 d1;
+ u8 __user *s = (u8 __user *)src;
+
if (__get_user(d1, s))
goto fault;
memcpy(buf, &d1, 1);
break;
- case 2:
+ }
+ case 2: {
+ u16 d2;
+ u16 __user *s = (u16 __user *)src;
+
if (__get_user(d2, s))
goto fault;
memcpy(buf, &d2, 2);
break;
- case 4:
+ }
+ case 4: {
+ u32 d4;
+ u32 __user *s = (u32 __user *)src;
+
if (__get_user(d4, s))
goto fault;
memcpy(buf, &d4, 4);
break;
- case 8:
+ }
+ case 8: {
+ u64 d8;
+ u64 __user *s = (u64 __user *)src;
if (__get_user(d8, s))
goto fault;
memcpy(buf, &d8, 8);
break;
+ }
default:
WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size);
return ES_UNSUPPORTED;
@@ -615,7 +605,7 @@ int __init sev_es_efi_map_ghcbs(pgd_t *pgd)
int cpu;
u64 pfn;
- if (!sev_es_active())
+ if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
return 0;
pflags = _PAGE_NX | _PAGE_RW;
@@ -648,7 +638,8 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
ghcb_set_rdx(ghcb, regs->dx);
}
- ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_MSR, exit_info_1, 0);
+ ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_MSR,
+ exit_info_1, 0);
if ((ret == ES_OK) && (!exit_info_1)) {
regs->ax = ghcb->save.rax;
@@ -774,7 +765,7 @@ void __init sev_es_init_vc_handling(void)
BUILD_BUG_ON(offsetof(struct sev_es_runtime_data, ghcb_page) % PAGE_SIZE);
- if (!sev_es_active())
+ if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT))
return;
if (!sev_es_check_cpu_features())
@@ -787,7 +778,6 @@ void __init sev_es_init_vc_handling(void)
for_each_possible_cpu(cpu) {
alloc_runtime_data(cpu);
init_ghcb(cpu);
- setup_vc_stacks(cpu);
}
sev_es_setup_play_dead();
@@ -867,7 +857,7 @@ static enum es_result vc_do_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt,
ghcb_set_sw_scratch(ghcb, ghcb_pa + offsetof(struct ghcb, shared_buffer));
- return sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, exit_info_1, exit_info_2);
+ return sev_es_ghcb_hv_call(ghcb, true, ctxt, exit_code, exit_info_1, exit_info_2);
}
static enum es_result vc_handle_mmio_twobyte_ops(struct ghcb *ghcb,
@@ -1117,7 +1107,7 @@ static enum es_result vc_handle_dr7_write(struct ghcb *ghcb,
/* Using a value of 0 for ExitInfo1 means RAX holds the value */
ghcb_set_rax(ghcb, val);
- ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WRITE_DR7, 0, 0);
+ ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_WRITE_DR7, 0, 0);
if (ret != ES_OK)
return ret;
@@ -1147,7 +1137,7 @@ static enum es_result vc_handle_dr7_read(struct ghcb *ghcb,
static enum es_result vc_handle_wbinvd(struct ghcb *ghcb,
struct es_em_ctxt *ctxt)
{
- return sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WBINVD, 0, 0);
+ return sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_WBINVD, 0, 0);
}
static enum es_result vc_handle_rdpmc(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
@@ -1156,7 +1146,7 @@ static enum es_result vc_handle_rdpmc(struct ghcb *ghcb, struct es_em_ctxt *ctxt
ghcb_set_rcx(ghcb, ctxt->regs->cx);
- ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_RDPMC, 0, 0);
+ ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_RDPMC, 0, 0);
if (ret != ES_OK)
return ret;
@@ -1197,7 +1187,7 @@ static enum es_result vc_handle_vmmcall(struct ghcb *ghcb,
if (x86_platform.hyper.sev_es_hcall_prepare)
x86_platform.hyper.sev_es_hcall_prepare(ghcb, ctxt->regs);
- ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_VMMCALL, 0, 0);
+ ret = sev_es_ghcb_hv_call(ghcb, true, ctxt, SVM_EXIT_VMMCALL, 0, 0);
if (ret != ES_OK)
return ret;
@@ -1319,13 +1309,26 @@ static __always_inline void vc_forward_exception(struct es_em_ctxt *ctxt)
}
}
-static __always_inline bool on_vc_fallback_stack(struct pt_regs *regs)
+static __always_inline bool is_vc2_stack(unsigned long sp)
{
- unsigned long sp = (unsigned long)regs;
-
return (sp >= __this_cpu_ist_bottom_va(VC2) && sp < __this_cpu_ist_top_va(VC2));
}
+static __always_inline bool vc_from_invalid_context(struct pt_regs *regs)
+{
+ unsigned long sp, prev_sp;
+
+ sp = (unsigned long)regs;
+ prev_sp = regs->sp;
+
+ /*
+ * If the code was already executing on the VC2 stack when the #VC
+ * happened, let it proceed to the normal handling routine. This way the
+ * code executing on the VC2 stack can cause #VC exceptions to get handled.
+ */
+ return is_vc2_stack(sp) && !is_vc2_stack(prev_sp);
+}
+
static bool vc_raw_handle_exception(struct pt_regs *regs, unsigned long error_code)
{
struct ghcb_state state;
@@ -1406,7 +1409,7 @@ DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication)
* But keep this here in case the noinstr annotations are violated due
* to bug elsewhere.
*/
- if (unlikely(on_vc_fallback_stack(regs))) {
+ if (unlikely(vc_from_invalid_context(regs))) {
instrumentation_begin();
panic("Can't handle #VC exception from unsupported context\n");
instrumentation_end();
generated by cgit v1.2.3 (git 2.46.0) at 2025-11-06 19:24:53 +0000