Re: [PATCH v6 14/16] KVM: x86/tdp_mmu: TDX: Implement merge pages into a large page
From: Binbin Wu
Date: Wed Nov 22 2023 - 02:50:56 EST
On 11/7/2023 11:00 PM, isaku.yamahata@xxxxxxxxx wrote:
From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
Implement merge_private_stp callback.
Not just merge_private_stp, but also unzap_private_spte.
Also, for the shortlog, should it be "KVM: VMX" instead of "KVM:
x86/tdp_mmu"?
Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
---
arch/x86/kvm/vmx/tdx.c | 72 ++++++++++++++++++++++++++++++++++++
arch/x86/kvm/vmx/tdx_arch.h | 1 +
arch/x86/kvm/vmx/tdx_errno.h | 2 +
arch/x86/kvm/vmx/tdx_ops.h | 6 +++
4 files changed, 81 insertions(+)
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 91eca578a7da..df53a971ff21 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1684,6 +1684,49 @@ static int tdx_sept_split_private_spt(struct kvm *kvm, gfn_t gfn,
return 0;
}
+static int tdx_sept_merge_private_spt(struct kvm *kvm, gfn_t gfn,
+ enum pg_level level, void *private_spt)
+{
+ int tdx_level = pg_level_to_tdx_sept_level(level);
+ struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
+ struct tdx_module_args out;
+ gpa_t gpa = gfn_to_gpa(gfn) & KVM_HPAGE_MASK(level);
+ u64 err;
+
+ /* See comment in tdx_sept_set_private_spte() */
+ err = tdh_mem_page_promote(kvm_tdx->tdr_pa, gpa, tdx_level, &out);
+ if (unlikely(err == TDX_ERROR_SEPT_BUSY))
+ return -EAGAIN;
+ if (unlikely(err == (TDX_EPT_INVALID_PROMOTE_CONDITIONS |
+ TDX_OPERAND_ID_RCX)))
+ /*
+ * Some pages are accepted, some pending. Need to wait for TD
+ * to accept all pages. Tell it the caller.
+ */
+ return -EAGAIN;
+ if (KVM_BUG_ON(err, kvm)) {
+ pr_tdx_error(TDH_MEM_PAGE_PROMOTE, err, &out);
+ return -EIO;
+ }
+ WARN_ON_ONCE(out.rcx != __pa(private_spt));
+
+ /*
+ * TDH.MEM.PAGE.PROMOTE frees the Secure-EPT page for the lower level.
Is it better to use "unlink" instead of "free" to avoid confusion?
+ * Flush cache for reuse.
+ */
+ do {
+ err = tdh_phymem_page_wbinvd(set_hkid_to_hpa(__pa(private_spt),
+ to_kvm_tdx(kvm)->hkid));
+ } while (unlikely(err == (TDX_OPERAND_BUSY | TDX_OPERAND_ID_RCX)));
+ if (WARN_ON_ONCE(err)) {
+ pr_tdx_error(TDH_PHYMEM_PAGE_WBINVD, err, NULL);
+ return -EIO;
+ }
+
+ tdx_clear_page(__pa(private_spt), PAGE_SIZE);
+ return 0;
+}
+
static int tdx_sept_zap_private_spte(struct kvm *kvm, gfn_t gfn,
enum pg_level level)
{
@@ -1758,6 +1801,33 @@ static void tdx_track(struct kvm *kvm)
}
+static int tdx_sept_unzap_private_spte(struct kvm *kvm, gfn_t gfn,
+ enum pg_level level)
+{
+ int tdx_level = pg_level_to_tdx_sept_level(level);
+ struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
+ gpa_t gpa = gfn_to_gpa(gfn) & KVM_HPAGE_MASK(level);
+ struct tdx_module_args out;
+ u64 err;
+
+ do {
+ err = tdh_mem_range_unblock(kvm_tdx->tdr_pa, gpa, tdx_level, &out);
+
+ /*
+ * tdh_mem_range_block() is accompanied with tdx_track() via kvm
+ * remote tlb flush. Wait for the caller of
+ * tdh_mem_range_block() to complete TDX track.
+ */
+ } while (err == (TDX_TLB_TRACKING_NOT_DONE | TDX_OPERAND_ID_SEPT));
+ if (unlikely(err == TDX_ERROR_SEPT_BUSY))
+ return -EAGAIN;
+ if (KVM_BUG_ON(err, kvm)) {
+ pr_tdx_error(TDH_MEM_RANGE_UNBLOCK, err, &out);
+ return -EIO;
+ }
+ return 0;
+}
+
static int tdx_sept_free_private_spt(struct kvm *kvm, gfn_t gfn,
enum pg_level level, void *private_spt)
{
@@ -3204,9 +3274,11 @@ int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops)
x86_ops->link_private_spt = tdx_sept_link_private_spt;
x86_ops->free_private_spt = tdx_sept_free_private_spt;
x86_ops->split_private_spt = tdx_sept_split_private_spt;
+ x86_ops->merge_private_spt = tdx_sept_merge_private_spt;
x86_ops->set_private_spte = tdx_sept_set_private_spte;
x86_ops->remove_private_spte = tdx_sept_remove_private_spte;
x86_ops->zap_private_spte = tdx_sept_zap_private_spte;
+ x86_ops->unzap_private_spte = tdx_sept_unzap_private_spte;
return 0;
diff --git a/arch/x86/kvm/vmx/tdx_arch.h b/arch/x86/kvm/vmx/tdx_arch.h
index cab6a74446a0..fb7e54953a85 100644
--- a/arch/x86/kvm/vmx/tdx_arch.h
+++ b/arch/x86/kvm/vmx/tdx_arch.h
@@ -29,6 +29,7 @@
#define TDH_MNG_KEY_FREEID 20
#define TDH_MNG_INIT 21
#define TDH_VP_INIT 22
+#define TDH_MEM_PAGE_PROMOTE 23
#define TDH_MEM_SEPT_RD 25
#define TDH_VP_RD 26
#define TDH_MNG_KEY_RECLAIMID 27
diff --git a/arch/x86/kvm/vmx/tdx_errno.h b/arch/x86/kvm/vmx/tdx_errno.h
index bb093e292fef..940d6de332eb 100644
--- a/arch/x86/kvm/vmx/tdx_errno.h
+++ b/arch/x86/kvm/vmx/tdx_errno.h
@@ -23,6 +23,8 @@
#define TDX_FLUSHVP_NOT_DONE 0x8000082400000000ULL
#define TDX_EPT_WALK_FAILED 0xC0000B0000000000ULL
#define TDX_EPT_ENTRY_NOT_FREE 0xC0000B0200000000ULL
+#define TDX_TLB_TRACKING_NOT_DONE 0xC0000B0800000000ULL
+#define TDX_EPT_INVALID_PROMOTE_CONDITIONS 0xC0000B0900000000ULL
#define TDX_EPT_ENTRY_STATE_INCORRECT 0xC0000B0D00000000ULL
/*
diff --git a/arch/x86/kvm/vmx/tdx_ops.h b/arch/x86/kvm/vmx/tdx_ops.h
index 38ab0ab1509c..774fee3b2d46 100644
--- a/arch/x86/kvm/vmx/tdx_ops.h
+++ b/arch/x86/kvm/vmx/tdx_ops.h
@@ -190,6 +190,12 @@ static inline u64 tdh_mem_page_demote(hpa_t tdr, gpa_t gpa, int level, hpa_t pag
return tdx_seamcall_sept(TDH_MEM_PAGE_DEMOTE, gpa | level, tdr, page, 0, out);
}
+static inline u64 tdh_mem_page_promote(hpa_t tdr, gpa_t gpa, int level,
+ struct tdx_module_args *out)
+{
+ return tdx_seamcall_sept(TDH_MEM_PAGE_PROMOTE, gpa | level, tdr, 0, 0, out);
+}
+
static inline u64 tdh_mr_extend(hpa_t tdr, gpa_t gpa,
struct tdx_module_args *out)
{