On 27/06/18 14:47, Suzuki K Poulose wrote:

Hi Marc,

On 27/06/18 13:20, Marc Zyngier wrote:

quoted

The {pmd,pud,pgd}_populate accessors usage in the kernel have always
been a bit weird in KVM. We don't have a struct mm to pass (and
neither does the kernel most of the time, but still...), and
the 32bit code has all kind of cache maintenance that doesn't make
sense on ARMv7+ when MP extensions are mandatory (which is the
case when the VEs are present).

Let's bite the bullet and provide our own implementations. The
only bit of architectural code left has to do with building the table
entry itself (arm64 having up to 52bit PA, arm lacking PUD level).

Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Christoffer Dall <redacted>
Signed-off-by: Marc Zyngier <redacted>
---
  arch/arm/include/asm/kvm_mmu.h   | 4 ++++
  arch/arm64/include/asm/kvm_mmu.h | 7 +++++++
  virt/kvm/arm/mmu.c               | 8 +++++---
  3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index b2feaea1434c..265ea9cf7df7 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h

@@ -75,6 +75,10 @@ phys_addr_t kvm_get_idmap_vector(void);
  int kvm_mmu_init(void);
  void kvm_clear_hyp_idmap(void);
  
+#define kvm_mk_pmd(ptep)	__pmd(__pa(ptep) | PMD_TYPE_TABLE)
+#define kvm_mk_pud(pmdp)	__pud(__pa(pmdp) | PMD_TYPE_TABLE)
+#define kvm_mk_pgd(pudp)	({ BUILD_BUG(); 0; })
+
  static inline pte_t kvm_s2pte_mkwrite(pte_t pte)
  {
  	pte_val(pte) |= L_PTE_S2_RDWR;

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 25c9a91f6a87..2f05be2bed63 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h

@@ -169,6 +169,13 @@ phys_addr_t kvm_get_idmap_vector(void);
  int kvm_mmu_init(void);
  void kvm_clear_hyp_idmap(void);
  
+#define kvm_mk_pmd(ptep)					\
+	__pmd(__phys_to_pmd_val(__pa(ptep) | PMD_TYPE_TABLE))
+#define kvm_mk_pud(pmdp)					\
+	__pud(__phys_to_pud_val(__pa(pmdp) | PMD_TYPE_TABLE))
+#define kvm_mk_pgd(pudp)					\
+	__pgd(__phys_to_pgd_val(__pa(pudp) | PUD_TYPE_TABLE))
+

I believe this is wrong, as the __phys_to_p.d_val could strip of the
TABLE bit. The correct usage is :

__pXd(__phys_to_pXd_val(__pa(ptr)) | PxD_TYPE_TABLE)

Ah, you're absolutely correct! Fixed now.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...