Hi,

On 5/25/23 3:58 PM, Kirill A. Shutemov wrote:

TDX code is going to provide guest.enc_status_change_prepare() that is able to fail.

You can add some info about why you need this?

Add a way to return an error from the callback.

While there, fix enc_status_change_finish_noop(). It is defined as always-fail now which doesn't make sense for noop.

IMO, since the above change is an independent fix, I think it is better to split this into a separate patch.

Other than above suggestions, the rest of the changes looks fine.

Signed-off-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: stable@vger.kernel.org

---

arch/x86/include/asm/x86_init.h | 2 +- arch/x86/kernel/x86_init.c | 4 ++-- arch/x86/mm/mem_encrypt_amd.c | 4 +++- arch/x86/mm/pat/set_memory.c | 3 ++- 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h index 88085f369ff6..1ca9701917c5 100644 --- a/arch/x86/include/asm/x86_init.h +++ b/arch/x86/include/asm/x86_init.h @@ -150,7 +150,7 @@ struct x86_init_acpi {

• @enc_cache_flush_required Returns true if a cache flush is needed before changing page encryption status

*/ struct x86_guest {

• void (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc);

• bool (*enc_status_change_prepare)(unsigned long vaddr, int npages, bool enc); bool (*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 d82f4fa2f1bf..64664311ac2b 100644 --- a/arch/x86/kernel/x86_init.c +++ b/arch/x86/kernel/x86_init.c @@ -130,8 +130,8 @@ struct x86_cpuinit_ops x86_cpuinit = { static void default_nmi_init(void) { }; -static void enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool enc) { } -static bool enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return false; } +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 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 e0b51c09109f..4f95c449a406 100644 --- a/arch/x86/mm/mem_encrypt_amd.c +++ b/arch/x86/mm/mem_encrypt_amd.c @@ -319,7 +319,7 @@ static void enc_dec_hypercall(unsigned long vaddr, int npages, bool enc) #endif } -static void amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc) +static bool amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc) { /* * To maintain the security guarantees of SEV-SNP guests, make sure @@ -327,6 +327,8 @@ static void 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 true unconditionally: return value doesn't matter for the SEV side */ diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index 7159cf787613..b8f48ebe753c 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -2151,7 +2151,8 @@ 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. */

• x86_platform.guest.enc_status_change_prepare(addr, numpages, enc);

• if (!x86_platform.guest.enc_status_change_prepare(addr, numpages, enc))

• return -EIO;
  

ret = __change_page_attr_set_clr(&cpa, 1);