| Message ID | 16ebf3b34cf1a2346ac6a58f4dc720abf74daab4.1705965634.git.isaku.yamahata@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM TDX basic feature support | expand |
On 1/23/2024 7:52 AM, isaku.yamahata@intel.com wrote: > From: Isaku Yamahata <isaku.yamahata@intel.com> > > Add helper functions to allocate/free TDX private host key id (HKID). > > The memory controller encrypts TDX memory with the assigned TDX HKIDs. The > global TDX HKID is to encrypt the TDX module, its memory, and some dynamic > data (TDR). The private TDX HKID is assigned to guest TD to encrypt guest > memory and the related data. When VMM releases an encrypted page for > reuse, the page needs a cache flush with the used HKID. VMM needs the > global TDX HKID and the private TDX HKIDs to flush encrypted pages. > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > --- > v18: > - Moved the functions to kvm tdx from arch/x86/virt/vmx/tdx/ > - Drop exporting symbols as the host tdx does. > --- > arch/x86/kvm/vmx/tdx.c | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > index 9d3f593eacb8..ee9d6a687d93 100644 > --- a/arch/x86/kvm/vmx/tdx.c > +++ b/arch/x86/kvm/vmx/tdx.c > @@ -11,6 +11,35 @@ > #undef pr_fmt > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > > +/* > + * Key id globally used by TDX module: TDX module maps TDR with this TDX global > + * key id. TDR includes key id assigned to the TD. Then TDX module maps other > + * TD-related pages with the assigned key id. TDR requires this TDX global key > + * id for cache flush unlike other TD-related pages. > + */ > +/* TDX KeyID pool */ > +static DEFINE_IDA(tdx_guest_keyid_pool); > + > +static int __used tdx_guest_keyid_alloc(void) > +{ > + if (WARN_ON_ONCE(!tdx_guest_keyid_start || !tdx_nr_guest_keyids)) > + return -EINVAL; > + > + /* The first keyID is reserved for the global key. */ Seems no need to add the comment here any more. > + return ida_alloc_range(&tdx_guest_keyid_pool, tdx_guest_keyid_start, > + tdx_guest_keyid_start + tdx_nr_guest_keyids - 1, > + GFP_KERNEL); > +} > + > +static void __used tdx_guest_keyid_free(int keyid) > +{ > + /* keyid = 0 is reserved. */ > + if (WARN_ON_ONCE(keyid <= 0)) Why not use tdx_guest_keyid_start and its range directly for the check? > + return; > + > + ida_free(&tdx_guest_keyid_pool, keyid); > +} > + > static int __init tdx_module_setup(void) > { > int ret;
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 9d3f593eacb8..ee9d6a687d93 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -11,6 +11,35 @@ #undef pr_fmt #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +/* + * Key id globally used by TDX module: TDX module maps TDR with this TDX global + * key id. TDR includes key id assigned to the TD. Then TDX module maps other + * TD-related pages with the assigned key id. TDR requires this TDX global key + * id for cache flush unlike other TD-related pages. + */ +/* TDX KeyID pool */ +static DEFINE_IDA(tdx_guest_keyid_pool); + +static int __used tdx_guest_keyid_alloc(void) +{ + if (WARN_ON_ONCE(!tdx_guest_keyid_start || !tdx_nr_guest_keyids)) + return -EINVAL; + + /* The first keyID is reserved for the global key. */ + return ida_alloc_range(&tdx_guest_keyid_pool, tdx_guest_keyid_start, + tdx_guest_keyid_start + tdx_nr_guest_keyids - 1, + GFP_KERNEL); +} + +static void __used tdx_guest_keyid_free(int keyid) +{ + /* keyid = 0 is reserved. */ + if (WARN_ON_ONCE(keyid <= 0)) + return; + + ida_free(&tdx_guest_keyid_pool, keyid); +} + static int __init tdx_module_setup(void) { int ret;