x86/sev: Make enc_dec_hypercall() accept a size instead of npages
enc_dec_hypercall() accepted a page count instead of a size, which
forced its callers to round up. As a result, non-page aligned
vaddrs caused pages to be spuriously marked as decrypted via the
encryption status hypercall, which in turn caused consistent
corruption of pages during live migration. Live migration requires
accurate encryption status information to avoid migrating pages
from the wrong perspective.
BUG=b/297544590
TEST=presubmit
RELEASE_NOTE=None
cos-patch: bug
Fixes: 064ce6c550a0 ("mm: x86: Invoke hypercall when page encryption status is changed")
Signed-off-by: Steve Rutherford <srutherford@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Tested-by: Ben Hillier <bhillier@google.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230824223731.2055016-1-srutherford@google.com
Change-Id: I09c552b5ce1a030030d7585cbff29a309b5e680a
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/56808
Main-Branch-Verified: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Arnav Kansal <rnv@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h
index a912ef9..73640f1 100644
--- a/arch/x86/include/asm/mem_encrypt.h
+++ b/arch/x86/include/asm/mem_encrypt.h
@@ -45,8 +45,8 @@ void __init sme_enable(struct boot_params *bp);
int __init early_set_memory_decrypted(unsigned long vaddr, unsigned long size);
int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size);
-void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages,
- bool enc);
+void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr,
+ unsigned long size, bool enc);
void __init mem_encrypt_free_decrypted_mem(void);
@@ -88,7 +88,7 @@ early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0;
static inline int __init
early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0; }
static inline void __init
-early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages, bool enc) {}
+early_set_mem_enc_dec_hypercall(unsigned long vaddr, unsigned long size, bool enc) {}
static inline void mem_encrypt_free_decrypted_mem(void) { }
diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
index 7428c23..3cd4b1c 100644
--- a/arch/x86/include/asm/set_memory.h
+++ b/arch/x86/include/asm/set_memory.h
@@ -82,7 +82,7 @@ int set_pages_rw(struct page *page, int numpages);
int set_direct_map_invalid_noflush(struct page *page);
int set_direct_map_default_noflush(struct page *page);
-void notify_range_enc_status_changed(unsigned long vaddr, int npages, bool enc);
+void notify_range_enc_status_changed(unsigned long vaddr, unsigned long size, bool enc);
extern int kernel_set_to_readonly;
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 98b7724..251fdc5 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -909,10 +909,8 @@ static void __init kvm_init_platform(void)
* Ensure that _bss_decrypted section is marked as decrypted in the
* shared pages list.
*/
- nr_pages = DIV_ROUND_UP(__end_bss_decrypted - __start_bss_decrypted,
- PAGE_SIZE);
early_set_mem_enc_dec_hypercall((unsigned long)__start_bss_decrypted,
- nr_pages, 0);
+ __end_bss_decrypted - __start_bss_decrypted, 0);
/*
* If not booted using EFI, enable Live migration support.
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 0cb04908..99d0f7f 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -228,11 +228,10 @@ static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)
return pfn;
}
-void notify_range_enc_status_changed(unsigned long vaddr, int npages, bool enc)
+void notify_range_enc_status_changed(unsigned long vaddr, unsigned long size, bool enc)
{
#ifdef CONFIG_PARAVIRT
- unsigned long sz = npages << PAGE_SHIFT;
- unsigned long vaddr_end = vaddr + sz;
+ unsigned long vaddr_end = vaddr + size;
while (vaddr < vaddr_end) {
int psize, pmask, level;
@@ -395,7 +394,7 @@ static int __init early_set_memory_enc_dec(unsigned long vaddr,
ret = 0;
- notify_range_enc_status_changed(start, PAGE_ALIGN(size) >> PAGE_SHIFT, enc);
+ notify_range_enc_status_changed(start, PAGE_ALIGN(size), enc);
out:
__flush_tlb_all();
return ret;
@@ -440,9 +439,9 @@ bool noinstr sev_es_active(void)
return sev_status & MSR_AMD64_SEV_ES_ENABLED;
}
-void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages, bool enc)
+void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, unsigned long size, bool enc)
{
- notify_range_enc_status_changed(vaddr, npages, enc);
+ notify_range_enc_status_changed(vaddr, size, enc);
}
/* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 449e6bb..ec7938e 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2016,7 +2016,7 @@ static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)
* Notify hypervisor that a given memory range is mapped encrypted
* or decrypted.
*/
- notify_range_enc_status_changed(addr, numpages, enc);
+ notify_range_enc_status_changed(addr, numpages << PAGE_SHIFT, enc);
return ret;
}
