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>,
Dave Hansen <dave.hansen@linux.intel.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
"H. Peter Anvin" <hpa@zytor.com>,
Michael Roth <michael.roth@amd.com>,
Joerg Roedel <jroedel@suse.de>, Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH v1 1/2] x86/sev: Use per-CPU PSC structure in prep for unaccepted memory support
Date: Fri, 29 Jul 2022 09:01:14 -0500 [thread overview]
Message-ID: <658c455c40e8950cb046dd885dd19dc1c52d060a.1659103274.git.thomas.lendacky@amd.com> (raw)
In-Reply-To: <cover.1659103274.git.thomas.lendacky@amd.com>
In advance of providing support for unaccepted memory, switch from using
kmalloc() for allocating the Page State Change structure to using a
per-CPU structure. This is needed to avoid a possible recursive call into
set_pages_state() if the allocation requires (more) memory to be accepted,
which would result in a hang.
Protect the use of the per-CPU structure by disabling interrupts during
memory acceptance. Since the set_pages_state() path is the only path into
vmgexit_psc(), rename vmgexit_psc() to __vmgexit_psc() and remove the
calls to disable interrupts which are now performed by set_pages_state().
Even with interrupts disabled, an NMI can be raised while performing
memory acceptance. The NMI could then cause further memory acceptance to
performed. To prevent corruption to the per-CPU structure, use the PSC
MSR protocol in this situation.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/kernel/sev.c | 60 ++++++++++++++++++++++++++++---------------
1 file changed, 39 insertions(+), 21 deletions(-)
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index c05f0124c410..1f7f6205c4f6 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -104,6 +104,15 @@ struct sev_es_runtime_data {
* is currently unsupported in SEV-ES guests.
*/
unsigned long dr7;
+
+ /*
+ * Page State Change structure for use when accepting memory or when
+ * changing page state. Interrupts are disabled when using the structure
+ * but an NMI could still be raised, so use a flag to indicate when the
+ * structure is in use and use the MSR protocol in these cases.
+ */
+ struct snp_psc_desc psc_desc;
+ bool psc_active;
};
struct ghcb_state {
@@ -660,7 +669,7 @@ static void pvalidate_pages(unsigned long vaddr, unsigned int npages, bool valid
}
}
-static void __init early_set_pages_state(unsigned long paddr, unsigned int npages, enum psc_op op)
+static void early_set_pages_state(unsigned long paddr, unsigned int npages, enum psc_op op)
{
unsigned long paddr_end;
u64 val;
@@ -742,26 +751,17 @@ void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op
WARN(1, "invalid memory op %d\n", op);
}
-static int vmgexit_psc(struct snp_psc_desc *desc)
+static int __vmgexit_psc(struct snp_psc_desc *desc)
{
int cur_entry, end_entry, ret = 0;
struct snp_psc_desc *data;
struct ghcb_state state;
struct es_em_ctxt ctxt;
- unsigned long flags;
struct ghcb *ghcb;
- /*
- * __sev_get_ghcb() needs to run with IRQs disabled because it is using
- * a per-CPU GHCB.
- */
- local_irq_save(flags);
-
ghcb = __sev_get_ghcb(&state);
- if (!ghcb) {
- ret = 1;
- goto out_unlock;
- }
+ if (!ghcb)
+ return 1;
/* Copy the input desc into GHCB shared buffer */
data = (struct snp_psc_desc *)ghcb->shared_buffer;
@@ -820,9 +820,6 @@ static int vmgexit_psc(struct snp_psc_desc *desc)
out:
__sev_put_ghcb(&state);
-out_unlock:
- local_irq_restore(flags);
-
return ret;
}
@@ -861,18 +858,32 @@ static void __set_pages_state(struct snp_psc_desc *data, unsigned long vaddr,
i++;
}
- if (vmgexit_psc(data))
+ if (__vmgexit_psc(data))
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC);
}
static void set_pages_state(unsigned long vaddr, unsigned int npages, int op)
{
unsigned long vaddr_end, next_vaddr;
+ struct sev_es_runtime_data *data;
struct snp_psc_desc *desc;
+ unsigned long flags;
- desc = kmalloc(sizeof(*desc), GFP_KERNEL_ACCOUNT);
- if (!desc)
- panic("SNP: failed to allocate memory for PSC descriptor\n");
+ /* Disable interrupts since a per-CPU PSC and per-CPU GHCB are used. */
+ local_irq_save(flags);
+
+ data = this_cpu_read(runtime_data);
+ if (!data || data->psc_active) {
+ /* No per-CPU PSC or it is active, use the MSR protocol. */
+ early_set_pages_state(__pa(vaddr), npages, op);
+ goto out;
+ }
+
+ /* Mark the PSC in use. */
+ data->psc_active = true;
+ barrier();
+
+ desc = &data->psc_desc;
vaddr = vaddr & PAGE_MASK;
vaddr_end = vaddr + (npages << PAGE_SHIFT);
@@ -887,7 +898,12 @@ static void set_pages_state(unsigned long vaddr, unsigned int npages, int op)
vaddr = next_vaddr;
}
- kfree(desc);
+ /* Mark the PSC no longer in use. */
+ barrier();
+ data->psc_active = false;
+
+out:
+ local_irq_restore(flags);
}
void snp_set_memory_shared(unsigned long vaddr, unsigned int npages)
@@ -1339,6 +1355,8 @@ static void __init alloc_runtime_data(int cpu)
panic("Can't allocate SEV-ES runtime data");
per_cpu(runtime_data, cpu) = data;
+
+ data->psc_active = false;
}
static void __init init_ghcb(int cpu)
--
2.36.1
next prev parent reply other threads:[~2022-07-29 14:01 UTC|newest]
Thread overview: 200+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-14 12:02 [PATCHv7 00/14] mm, x86/cc: Implement support for unaccepted memory Kirill A. Shutemov
2022-06-14 12:02 ` [PATCHv7 01/14] x86/boot: Centralize __pa()/__va() definitions Kirill A. Shutemov
2022-06-23 17:37 ` Dave Hansen
2022-06-14 12:02 ` [PATCHv7 02/14] mm: Add support for unaccepted memory Kirill A. Shutemov
2022-06-14 12:57 ` Gupta, Pankaj
2022-06-17 19:28 ` Tom Lendacky
2022-06-17 20:53 ` Tom Lendacky
2022-07-21 15:14 ` Borislav Petkov
2022-07-21 15:49 ` Dave Hansen
2022-07-22 19:18 ` Borislav Petkov
2022-07-22 19:30 ` Dave Hansen
2022-07-25 12:23 ` Borislav Petkov
2022-07-25 12:38 ` David Hildenbrand
2022-07-25 12:53 ` Borislav Petkov
2022-07-26 14:30 ` David Hildenbrand
2022-07-25 13:00 ` Mike Rapoport
2022-07-25 13:05 ` Borislav Petkov
2022-08-05 11:49 ` Vlastimil Babka
2022-08-05 12:09 ` David Hildenbrand
2022-08-05 13:38 ` Vlastimil Babka
2022-08-05 14:22 ` David Hildenbrand
2022-08-05 14:53 ` Dave Hansen
2022-08-05 14:41 ` Dave Hansen
2022-08-05 18:17 ` Vlastimil Babka
2022-08-08 15:55 ` Dave Hansen
2022-08-10 14:19 ` Mel Gorman
2022-08-15 21:08 ` Dionna Amalie Glaze
2022-08-15 22:02 ` Tom Lendacky
2022-08-29 16:02 ` Dionna Amalie Glaze
2022-08-29 16:19 ` Dave Hansen
2022-09-06 17:50 ` Dionna Amalie Glaze
2022-09-08 12:11 ` Mike Rapoport
2022-09-08 16:23 ` Dionna Amalie Glaze
2022-09-08 19:28 ` Mike Rapoport
2022-09-22 14:31 ` Tom Lendacky
2022-09-24 1:03 ` Kirill A. Shutemov
2022-09-24 9:36 ` Mike Rapoport
2022-09-26 12:10 ` Kirill A. Shutemov
2022-09-26 13:38 ` Tom Lendacky
2022-09-26 15:42 ` Kirill A. Shutemov
2022-09-26 15:42 ` Tom Lendacky
2022-06-14 12:02 ` [PATCHv7 03/14] mm: Report unaccepted memory in meminfo Kirill A. Shutemov
2022-07-26 14:33 ` David Hildenbrand
2022-06-14 12:02 ` [PATCHv7 04/14] efi/x86: Get full memory map in allocate_e820() Kirill A. Shutemov
2022-07-25 13:02 ` Borislav Petkov
2022-06-14 12:02 ` [PATCHv7 05/14] x86/boot: Add infrastructure required for unaccepted memory support Kirill A. Shutemov
2022-06-15 10:19 ` Peter Zijlstra
2022-06-15 15:05 ` Kirill A. Shutemov
2022-07-17 17:16 ` Borislav Petkov
2022-07-25 21:33 ` Borislav Petkov
2022-06-14 12:02 ` [PATCHv7 06/14] efi/x86: Implement support for unaccepted memory Kirill A. Shutemov
2022-06-22 19:58 ` Dave Hansen
2022-07-26 8:35 ` Borislav Petkov
2022-06-14 12:02 ` [PATCHv7 07/14] x86/boot/compressed: Handle " Kirill A. Shutemov
2022-06-14 12:02 ` [PATCHv7 08/14] x86/mm: Reserve unaccepted memory bitmap Kirill A. Shutemov
2022-07-26 9:07 ` Borislav Petkov
2022-11-30 1:28 ` Kirill A. Shutemov
2022-12-01 9:37 ` Mike Rapoport
2022-12-01 13:47 ` Kirill A. Shutemov
2022-06-14 12:02 ` [PATCHv7 09/14] x86/mm: Provide helpers for unaccepted memory Kirill A. Shutemov
2022-06-14 12:02 ` [PATCHv7 10/14] x86/mm: Avoid load_unaligned_zeropad() stepping into " Kirill A. Shutemov
2022-06-23 17:19 ` Dave Hansen
2022-07-26 10:21 ` Borislav Petkov
2022-08-02 23:46 ` Dave Hansen
2022-08-03 14:02 ` Dave Hansen
2022-08-11 11:26 ` Borislav Petkov
2022-08-13 16:11 ` Andy Lutomirski
2022-08-13 21:13 ` Kirill A. Shutemov
2022-08-13 16:04 ` Andy Lutomirski
2022-08-13 20:58 ` Kirill A. Shutemov
2022-07-26 17:25 ` Borislav Petkov
2022-07-26 17:46 ` Dave Hansen
2022-07-26 20:17 ` Andy Lutomirski
2022-08-09 11:38 ` Kirill A. Shutemov
2022-08-13 16:03 ` Andy Lutomirski
2022-08-13 21:02 ` Kirill A. Shutemov
2022-06-14 12:02 ` [PATCHv7 11/14] x86: Disable kexec if system has " Kirill A. Shutemov
2022-06-23 17:23 ` Dave Hansen
2022-06-23 21:48 ` Eric W. Biederman
2022-06-24 2:00 ` Kirill A. Shutemov
2022-06-28 23:51 ` Kirill A. Shutemov
2022-06-29 0:10 ` Dave Hansen
2022-06-29 0:59 ` Kirill A. Shutemov
2022-07-04 7:18 ` Dave Young
2022-06-14 12:02 ` [PATCHv7 12/14] x86/tdx: Make _tdx_hypercall() and __tdx_module_call() available in boot stub Kirill A. Shutemov
2022-06-23 17:25 ` Dave Hansen
2022-06-14 12:02 ` [PATCHv7 13/14] x86/tdx: Refactor try_accept_one() Kirill A. Shutemov
2022-06-23 17:31 ` Dave Hansen
2022-07-26 10:58 ` Borislav Petkov
2022-06-14 12:02 ` [PATCHv7 14/14] x86/tdx: Add unaccepted memory support Kirill A. Shutemov
2022-06-24 16:22 ` Dave Hansen
2022-06-27 10:42 ` Kirill A. Shutemov
2022-07-26 14:51 ` Borislav Petkov
2022-08-09 11:45 ` Kirill A. Shutemov
2022-08-10 10:27 ` Borislav Petkov
2022-06-24 16:37 ` [PATCHv7 00/14] mm, x86/cc: Implement support for unaccepted memory Peter Gonda
2022-06-24 16:57 ` Dave Hansen
2022-06-24 17:06 ` Marc Orr
2022-06-24 17:09 ` Dave Hansen
2022-06-24 17:15 ` Peter Gonda
2022-06-24 17:19 ` Marc Orr
2022-06-24 17:21 ` Peter Gonda
2022-06-24 17:47 ` Dave Hansen
2022-06-24 18:10 ` Peter Gonda
2022-06-24 18:13 ` Dave Hansen
2022-06-24 17:40 ` Michael Roth
2022-06-24 17:58 ` Michael Roth
2022-06-24 18:05 ` Peter Gonda
2022-06-27 11:30 ` Kirill A. Shutemov
2022-06-27 11:54 ` Ard Biesheuvel
2022-06-27 12:22 ` Kirill A. Shutemov
2022-06-27 16:17 ` Peter Gonda
2022-06-27 16:33 ` Ard Biesheuvel
2022-06-27 22:38 ` Kirill A. Shutemov
2022-06-28 17:17 ` Ard Biesheuvel
2022-07-18 17:21 ` Kirill A. Shutemov
2022-07-18 23:32 ` Dionna Amalie Glaze
2022-07-19 0:31 ` Dionna Amalie Glaze
2022-07-19 18:29 ` Dionna Amalie Glaze
2022-07-19 19:13 ` Borislav Petkov
2022-07-19 20:45 ` Ard Biesheuvel
2022-07-19 21:23 ` Borislav Petkov
2022-07-19 21:35 ` Dave Hansen
2022-07-19 21:50 ` Borislav Petkov
2022-07-19 22:01 ` Kirill A. Shutemov
2022-07-19 22:02 ` Dave Hansen
2022-07-19 22:08 ` Tom Lendacky
2022-07-20 0:26 ` Marc Orr
2022-07-20 5:44 ` Borislav Petkov
2022-07-20 17:03 ` Marc Orr
2022-07-22 15:07 ` Borislav Petkov
2022-07-21 17:12 ` Dave Hansen
2022-07-23 11:14 ` Ard Biesheuvel
2022-07-28 22:01 ` Dionna Amalie Glaze
2022-08-09 11:14 ` Kirill A. Shutemov
2022-08-09 11:36 ` Ard Biesheuvel
2022-08-09 11:54 ` Kirill A. Shutemov
2022-08-09 21:09 ` Dionna Amalie Glaze
2022-07-19 2:48 ` Yao, Jiewen
2022-07-29 14:01 ` [PATCH v1 0/2] Provide SEV-SNP " Tom Lendacky
2022-07-29 14:01 ` Tom Lendacky [this message]
2022-07-29 14:18 ` [PATCH v1 1/2] x86/sev: Use per-CPU PSC structure in prep for unaccepted memory support Dave Hansen
2022-07-29 14:25 ` Tom Lendacky
2022-07-29 19:08 ` Dave Hansen
2022-07-29 19:22 ` Tom Lendacky
2022-07-29 19:28 ` Dave Hansen
2022-07-29 20:12 ` Tom Lendacky
2022-08-03 18:11 ` [PATCH v1.1 0/2] Provide SEV-SNP support for unaccepted memory Tom Lendacky
2022-08-03 18:11 ` [PATCH v1.1 1/2] x86/sev: Use per-CPU PSC structure in prep for unaccepted memory support Tom Lendacky
2022-08-03 18:17 ` Dave Hansen
2022-08-03 18:21 ` Tom Lendacky
2022-08-03 18:24 ` Dave Hansen
2022-08-03 21:03 ` Tom Lendacky
2022-08-03 21:18 ` Dave Hansen
2022-08-03 21:34 ` Tom Lendacky
2022-08-03 21:48 ` Dave Hansen
2022-08-03 22:17 ` Tom Lendacky
2022-08-03 18:18 ` Tom Lendacky
2022-08-03 18:11 ` [PATCH v1.1 2/2] x86/sev: Add SNP-specific " Tom Lendacky
2022-07-29 14:01 ` [PATCH v1 " Tom Lendacky
2022-08-23 0:24 ` Dionna Amalie Glaze
2022-08-23 14:28 ` Tom Lendacky
2022-08-23 23:28 ` Dionna Amalie Glaze
2022-08-08 17:16 ` [PATCH v2 0/2] Provide SEV-SNP support for unaccepted memory Tom Lendacky
2022-08-08 17:16 ` [PATCH v2 1/2] x86/sev: Put PSC struct on the stack in prep for unaccepted memory support Tom Lendacky
2022-08-08 21:43 ` Dave Hansen
2022-08-08 22:18 ` Tom Lendacky
2022-08-08 22:33 ` Dave Hansen
2022-08-08 22:35 ` Tom Lendacky
2022-08-12 13:03 ` Borislav Petkov
2022-08-12 14:11 ` Tom Lendacky
2022-08-12 14:33 ` Borislav Petkov
2022-08-12 14:51 ` Tom Lendacky
2022-08-13 19:40 ` Borislav Petkov
2022-08-14 13:36 ` Tom Lendacky
2022-08-08 17:16 ` [PATCH v2 2/2] x86/sev: Add SNP-specific " Tom Lendacky
2022-08-15 15:57 ` [PATCH v3 0/2] Provide SEV-SNP support for unaccepted memory Tom Lendacky
2022-08-15 15:57 ` [PATCH v3 1/2] x86/sev: Put PSC struct on the stack in prep for unaccepted memory support Tom Lendacky
2022-08-17 16:08 ` Borislav Petkov
2022-08-17 21:17 ` Tom Lendacky
2022-08-15 15:57 ` [PATCH v3 2/2] x86/sev: Add SNP-specific " Tom Lendacky
2022-08-18 13:39 ` Borislav Petkov
2022-08-25 14:23 ` [PATCH v4 0/4] Provide SEV-SNP support for unaccepted memory Tom Lendacky
2022-08-25 14:23 ` [PATCH v4 1/4] x86/sev: Put PSC struct on the stack in prep for unaccepted memory support Tom Lendacky
2022-09-20 16:15 ` Borislav Petkov
2022-08-25 14:23 ` [PATCH v4 2/4] x86/sev: Allow for use of the early boot GHCB for PSC requests Tom Lendacky
2022-08-25 14:23 ` [PATCH v4 3/4] x86/sev: Use large PSC requests if applicable Tom Lendacky
2022-08-25 14:23 ` [PATCH v4 4/4] x86/sev: Add SNP-specific unaccepted memory support Tom Lendacky
2022-08-25 22:10 ` Dionna Amalie Glaze
2022-08-26 21:29 ` Tom Lendacky
2022-09-27 17:04 ` [PATCH v5 0/6] Provide SEV-SNP support for unaccepted memory Tom Lendacky
2022-09-27 17:04 ` [PATCH v5 1/6] x86/sev: Fix calculation of end address based on number of pages Tom Lendacky
2022-09-27 17:10 ` Dave Hansen
2022-09-27 20:45 ` Tom Lendacky
2022-09-27 19:04 ` Dionna Amalie Glaze
2022-09-27 17:04 ` [PATCH v5 2/6] " Tom Lendacky
2022-09-27 17:04 ` [PATCH v5 3/6] x86/sev: Put PSC struct on the stack in prep for unaccepted memory support Tom Lendacky
2022-09-27 17:04 ` [PATCH v5 4/6] x86/sev: Allow for use of the early boot GHCB for PSC requests Tom Lendacky
2022-09-27 17:04 ` [PATCH v5 5/6] x86/sev: Use large PSC requests if applicable Tom Lendacky
2022-09-27 17:04 ` [PATCH v5 6/6] x86/sev: Add SNP-specific unaccepted memory support Tom Lendacky
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