From: Tom Lendacky <thomas.lendacky@amd.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Joerg Roedel <jroedel@suse.de>,
Paolo Bonzini <pbonzini@redhat.com>,
Jim Mattson <jmattson@google.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH] x86/sev-es: Invalidate the GHCB after completing VMGEXIT
Date: Fri, 14 May 2021 14:12:33 -0500 [thread overview]
Message-ID: <fa408ec4020d7ab056875ec8c80d793b75f20a39.1621019553.git.thomas.lendacky@amd.com> (raw)
Since the VMGEXIT instruction can be issued from userspace, invalidate
the GHCB after performing VMGEXIT processing in the kernel.
Invalidation is only required after userspace is available, so call
vc_ghcb_invalidate() from sev_es_put_ghcb(). Update vc_ghcb_invalidate()
to additionally clear the GHCB exit code, so that a value of 0 is always
present outside VMGEXIT processing in the kernel.
Since vc_ghcb_invalidate() is part of sev-shared.c, move sev_es_put_ghcb()
down to after where sev-shared.c is included.
Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/kernel/sev-shared.c | 1 +
arch/x86/kernel/sev.c | 37 ++++++++++++++++++------------------
2 files changed, 20 insertions(+), 18 deletions(-)
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 6ec8b3bfd76e..9f90f460a28c 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -63,6 +63,7 @@ static bool sev_es_negotiate_protocol(void)
static __always_inline void vc_ghcb_invalidate(struct ghcb *ghcb)
{
+ ghcb->save.sw_exit_code = 0;
memset(ghcb->save.valid_bitmap, 0, sizeof(ghcb->save.valid_bitmap));
}
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 9578c82832aa..5ccb0218c885 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -221,24 +221,6 @@ static __always_inline struct ghcb *sev_es_get_ghcb(struct ghcb_state *state)
return ghcb;
}
-static __always_inline void sev_es_put_ghcb(struct ghcb_state *state)
-{
- struct sev_es_runtime_data *data;
- struct ghcb *ghcb;
-
- data = this_cpu_read(runtime_data);
- ghcb = &data->ghcb_page;
-
- if (state->ghcb) {
- /* Restore GHCB from Backup */
- *ghcb = *state->ghcb;
- data->backup_ghcb_active = false;
- state->ghcb = NULL;
- } else {
- data->ghcb_active = false;
- }
-}
-
/* Needed in vc_early_forward_exception */
void do_early_exception(struct pt_regs *regs, int trapnr);
@@ -461,6 +443,25 @@ static enum es_result vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt
/* Include code shared with pre-decompression boot stage */
#include "sev-shared.c"
+static __always_inline void sev_es_put_ghcb(struct ghcb_state *state)
+{
+ struct sev_es_runtime_data *data;
+ struct ghcb *ghcb;
+
+ data = this_cpu_read(runtime_data);
+ ghcb = &data->ghcb_page;
+
+ if (state->ghcb) {
+ /* Restore GHCB from Backup */
+ *ghcb = *state->ghcb;
+ data->backup_ghcb_active = false;
+ state->ghcb = NULL;
+ } else {
+ vc_ghcb_invalidate(ghcb);
+ data->ghcb_active = false;
+ }
+}
+
void noinstr __sev_es_nmi_complete(void)
{
struct ghcb_state state;
--
2.31.0
next reply other threads:[~2021-05-14 19:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-14 19:12 Tom Lendacky [this message]
2021-05-14 19:15 ` [PATCH] x86/sev-es: Invalidate the GHCB after completing VMGEXIT Tom Lendacky
2021-05-17 12:33 ` Joerg Roedel
2021-05-17 15:05 ` Tom Lendacky
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