[PATCH 06/13] x86/mm: Make x86_platform.guest.enc_status_change_*() return errno

From: Kirill A. Shutemov
Date: Thu Oct 05 2023 - 11:59:07 EST


TDX is going to have more than one reason to fail
enc_status_change_prepare().

Change the callback to return errno instead of assuming -EIO;
enc_status_change_finish() changed too to keep the interface symmetric.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/coco/tdx/tdx.c | 20 +++++++++++---------
arch/x86/hyperv/ivm.c | 9 +++------
arch/x86/include/asm/x86_init.h | 4 ++--
arch/x86/kernel/x86_init.c | 4 ++--
arch/x86/mm/mem_encrypt_amd.c | 8 ++++----
arch/x86/mm/pat/set_memory.c | 9 +++++----
6 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index 3e6dbd2199cf..46022283d955 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -776,28 +776,30 @@ static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc)
return true;
}

-static bool tdx_enc_status_change_prepare(unsigned long vaddr, int numpages,
- bool enc)
+static int tdx_enc_status_change_prepare(unsigned long vaddr, int numpages,
+ bool enc)
{
/*
* Only handle shared->private conversion here.
* See the comment in tdx_early_init().
*/
- if (enc)
- return tdx_enc_status_changed(vaddr, numpages, enc);
- return true;
+ if (enc && !tdx_enc_status_changed(vaddr, numpages, enc))
+ return -EIO;
+
+ return 0;
}

-static bool tdx_enc_status_change_finish(unsigned long vaddr, int numpages,
+static int tdx_enc_status_change_finish(unsigned long vaddr, int numpages,
bool enc)
{
/*
* Only handle private->shared conversion here.
* See the comment in tdx_early_init().
*/
- if (!enc)
- return tdx_enc_status_changed(vaddr, numpages, enc);
- return true;
+ if (!enc && !tdx_enc_status_changed(vaddr, numpages, enc))
+ return -EIO;
+
+ return 0;
}

void __init tdx_early_init(void)
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index c1088d3661d5..7d2241059d49 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -510,13 +510,12 @@ static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
* with host. This function works as wrap of hv_mark_gpa_visibility()
* with memory base and size.
*/
-static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
+static int hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
{
enum hv_mem_host_visibility visibility = enc ?
VMBUS_PAGE_NOT_VISIBLE : VMBUS_PAGE_VISIBLE_READ_WRITE;
u64 *pfn_array;
int ret = 0;
- bool result = true;
int i, pfn;

pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
@@ -530,17 +529,15 @@ static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bo
if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
ret = hv_mark_gpa_visibility(pfn, pfn_array,
visibility);
- if (ret) {
- result = false;
+ if (ret)
goto err_free_pfn_array;
- }
pfn = 0;
}
}

err_free_pfn_array:
kfree(pfn_array);
- return result;
+ return ret;
}

static bool hv_vtom_tlb_flush_required(bool private)
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index 5240d88db52a..5031cbc6e211 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -150,8 +150,8 @@ struct x86_init_acpi {
* @enc_cache_flush_required Returns true if a cache flush is needed before changing page encryption status
*/
struct x86_guest {
- bool (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc);
- bool (*enc_status_change_finish)(unsigned long vaddr, int npages, bool enc);
+ int (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc);
+ int (*enc_status_change_finish)(unsigned long vaddr, int npages, bool enc);
bool (*enc_tlb_flush_required)(bool enc);
bool (*enc_cache_flush_required)(void);
};
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index a37ebd3b4773..f0f54e109eb9 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -131,8 +131,8 @@ struct x86_cpuinit_ops x86_cpuinit = {

static void default_nmi_init(void) { };

-static bool enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool enc) { return true; }
-static bool enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return true; }
+static int enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool enc) { return 0; }
+static int enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return 0; }
static bool enc_tlb_flush_required_noop(bool enc) { return false; }
static bool enc_cache_flush_required_noop(void) { return false; }
static bool is_private_mmio_noop(u64 addr) {return false; }
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c
index 6faea41e99b6..9cbdfbf8cd45 100644
--- a/arch/x86/mm/mem_encrypt_amd.c
+++ b/arch/x86/mm/mem_encrypt_amd.c
@@ -318,7 +318,7 @@ static void enc_dec_hypercall(unsigned long vaddr, unsigned long size, bool enc)
#endif
}

-static bool amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)
+static int amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc)
{
/*
* To maintain the security guarantees of SEV-SNP guests, make sure
@@ -327,11 +327,11 @@ static bool amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool
if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && !enc)
snp_set_memory_shared(vaddr, npages);

- return true;
+ return 0;
}

/* Return true unconditionally: return value doesn't matter for the SEV side */
-static bool amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)
+static int amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc)
{
/*
* After memory is mapped encrypted in the page table, validate it
@@ -343,7 +343,7 @@ static bool amd_enc_status_change_finish(unsigned long vaddr, int npages, bool e
if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
enc_dec_hypercall(vaddr, npages << PAGE_SHIFT, enc);

- return true;
+ return 0;
}

static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index bda9f129835e..6fbf22d5fa56 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2152,8 +2152,9 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
cpa_flush(&cpa, x86_platform.guest.enc_cache_flush_required());

/* Notify hypervisor that we are about to set/clr encryption attribute. */
- if (!x86_platform.guest.enc_status_change_prepare(addr, numpages, enc))
- return -EIO;
+ ret = x86_platform.guest.enc_status_change_prepare(addr, numpages, enc);
+ if (ret)
+ return ret;

ret = __change_page_attr_set_clr(&cpa, 1);

@@ -2168,8 +2169,8 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)

/* Notify hypervisor that we have successfully set/clr encryption attribute. */
if (!ret) {
- if (!x86_platform.guest.enc_status_change_finish(addr, numpages, enc))
- ret = -EIO;
+ ret = x86_platform.guest.enc_status_change_finish(addr,
+ numpages, enc);
}

return ret;
--
2.41.0