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* [PATCH] x86/sev: Fully map the #VC exception stacks
@ 2021-10-01  4:40 Tom Lendacky
  2021-10-01  4:49 ` Tom Lendacky
  2021-10-01  8:57 ` Borislav Petkov
  0 siblings, 2 replies; 14+ messages in thread
From: Tom Lendacky @ 2021-10-01  4:40 UTC (permalink / raw)
  To: linux-kernel, x86
  Cc: Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	Joerg Roedel, Brijesh Singh

The size of the exception stacks was recently increased, resulting in
stack sizes greater than a page in size. The #VC exception handling was
only mapping the first (bottom) page, resulting in an SEV-ES guest failing
to boot.

Update setup_vc_stacks() to map all the pages of both the IST stack area
and the fallback stack area.

Fixes: 7fae4c24a2b8 ("x86: Increase exception stack sizes")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/x86/kernel/sev.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index a6895e440bc3..33e4704164cc 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -99,25 +99,33 @@ 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 map_vc_stack(unsigned long bot, unsigned long top,
+				phys_addr_t pa)
+{
+	while (bot < top) {
+		cea_set_pte((void *)bot, pa, PAGE_KERNEL);
+		bot += PAGE_SIZE;
+		pa += PAGE_SIZE;
+	}
+}
+
 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_stack(CEA_ESTACK_BOT(&cea->estacks, VC),
+		     CEA_ESTACK_TOP(&cea->estacks, VC),
+		     __pa(data->ist_stack));
 
 	/* 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);
+	map_vc_stack(CEA_ESTACK_BOT(&cea->estacks, VC2),
+		     CEA_ESTACK_TOP(&cea->estacks, VC2),
+		     __pa(data->fallback_stack));
 }
 
 static __always_inline bool on_vc_stack(struct pt_regs *regs)
-- 
2.33.0


^ permalink raw reply related	[flat|nested] 14+ messages in thread
end of thread, other threads:[~2021-10-06 19:56 UTC | newest]

Thread overview: 14+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-10-01  4:40 [PATCH] x86/sev: Fully map the #VC exception stacks Tom Lendacky
2021-10-01  4:49 ` Tom Lendacky
2021-10-01  8:57 ` Borislav Petkov
2021-10-01 11:50   ` Joerg Roedel
2021-10-01 12:58     ` Borislav Petkov
2021-10-01 13:00       ` Joerg Roedel
2021-10-01 13:29         ` Peter Zijlstra
2021-10-01 13:52         ` Borislav Petkov
2021-10-01 20:39           ` Borislav Petkov
2021-10-04 15:08             ` [PATCH] x86/sev: Make the #VC exception stacks part of the default stacks storage Borislav Petkov
2021-10-04 21:41               ` [PATCH -v2] " Borislav Petkov
2021-10-05 16:28                 ` Tom Lendacky
2021-10-05 20:32                 ` Brijesh Singh
2021-10-06 19:56                 ` [tip: x86/core] " tip-bot2 for Borislav Petkov

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