Move the location of sev_es_put_ghcb() in preparation for an update to it in a follow-on patch. This will better highlight the changes being made to the function.
No functional change.
Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler") Cc: stable@vger.kernel.org Signed-off-by: Tom Lendacky thomas.lendacky@amd.com --- arch/x86/kernel/sev.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 9578c82832aa..45e212675811 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 +443,24 @@ 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 { + data->ghcb_active = false; + } +} + void noinstr __sev_es_nmi_complete(void) { struct ghcb_state state;
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.
Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler") Cc: stable@vger.kernel.org Signed-off-by: Tom Lendacky thomas.lendacky@amd.com --- arch/x86/kernel/sev-shared.c | 1 + arch/x86/kernel/sev.c | 5 +++++ 2 files changed, 6 insertions(+)
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 45e212675811..4fa111becc93 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -457,6 +457,11 @@ static __always_inline void sev_es_put_ghcb(struct ghcb_state *state) data->backup_ghcb_active = false; state->ghcb = NULL; } else { + /* + * Invalidate the GHCB so a VMGEXIT instruction issued + * from userspace won't appear to be valid. + */ + vc_ghcb_invalidate(ghcb); data->ghcb_active = false; } }
The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: a50c5bebc99c525e7fbc059988c6a5ab8680cb76 Gitweb: https://git.kernel.org/tip/a50c5bebc99c525e7fbc059988c6a5ab8680cb76 Author: Tom Lendacky thomas.lendacky@amd.com AuthorDate: Mon, 17 May 2021 12:42:33 -05:00 Committer: Borislav Petkov bp@suse.de CommitterDate: Tue, 18 May 2021 07:06:29 +02:00
x86/sev-es: Invalidate the GHCB after completing VMGEXIT
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 it is always presented as 0 when VMGEXIT has been issued by anything else besides the kernel.
Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler") Signed-off-by: Tom Lendacky thomas.lendacky@amd.com Signed-off-by: Borislav Petkov bp@suse.de Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/5a8130462e4f0057ee1184509cd056eedd78742b.162127335... --- arch/x86/kernel/sev-shared.c | 1 + arch/x86/kernel/sev.c | 5 +++++ 2 files changed, 6 insertions(+)
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c index 6ec8b3b..9f90f46 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 45e2126..4fa111b 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -457,6 +457,11 @@ static __always_inline void sev_es_put_ghcb(struct ghcb_state *state) data->backup_ghcb_active = false; state->ghcb = NULL; } else { + /* + * Invalidate the GHCB so a VMGEXIT instruction issued + * from userspace won't appear to be valid. + */ + vc_ghcb_invalidate(ghcb); data->ghcb_active = false; } }
On Mon, May 17, 2021 at 12:42:33PM -0500, Tom Lendacky wrote:
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.
Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler") Cc: stable@vger.kernel.org Signed-off-by: Tom Lendacky thomas.lendacky@amd.com
Reviewed-by: Joerg Roedel jroedel@suse.de
The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: fea63d54f7a3e74f8ab489a8b82413a29849a594 Gitweb: https://git.kernel.org/tip/fea63d54f7a3e74f8ab489a8b82413a29849a594 Author: Tom Lendacky thomas.lendacky@amd.com AuthorDate: Mon, 17 May 2021 12:42:32 -05:00 Committer: Borislav Petkov bp@suse.de CommitterDate: Tue, 18 May 2021 06:49:37 +02:00
x86/sev-es: Move sev_es_put_ghcb() in prep for follow on patch
Move the location of sev_es_put_ghcb() in preparation for an update to it in a follow-on patch. This will better highlight the changes being made to the function.
No functional change.
Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler") Signed-off-by: Tom Lendacky thomas.lendacky@amd.com Signed-off-by: Borislav Petkov bp@suse.de Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/8c07662ec17d3d82e5c53841a1d9e766d3bdbab6.162127335... --- arch/x86/kernel/sev.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 9578c82..45e2126 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 +443,24 @@ 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 { + data->ghcb_active = false; + } +} + void noinstr __sev_es_nmi_complete(void) { struct ghcb_state state;
On Mon, May 17, 2021 at 12:42:32PM -0500, Tom Lendacky wrote:
Move the location of sev_es_put_ghcb() in preparation for an update to it in a follow-on patch. This will better highlight the changes being made to the function.
No functional change.
Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler") Cc: stable@vger.kernel.org Signed-off-by: Tom Lendacky thomas.lendacky@amd.com
Reviewed-by: Joerg Roedel jroedel@suse.de
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