XVM gas handling prototype

Cargo.toml

@@ -21,5 +21,7 @@ members = [
 	"precompiles/xcm",
 	"precompiles/xvm",
 
-	"contracts/*",
+	# Current build fails due to error associated with incorrect nightly usage
+	# but we use one from polkadot release so we probably shouldn't change it yet.
+	# "contracts/*",
 ]

chain-extensions/impls/xvm/src/lib.rs

@@ -47,26 +47,19 @@ where
 
         match func_id {
             XvmFuncId::XvmCall => {
-                // TODO: correct weight calculation directly from pallet!
-                let weight = 1_000_000_000;
-                env.charge_weight(weight)?;
+                // We need to immediately charge for the worst case scenario. Gas equals Weight in pallet-contracts context.
+                let remaining_weight = env.ext().gas_meter().gas_left();
+                let charged_weight = env.charge_weight(remaining_weight)?;
 
-                // Prepare parameters
                 let caller = env.ext().caller().clone();
 
-                let XvmCallArgs {
-                    vm_id,
-                    to,
-                    input,
-                } = env.read_as_unbounded(env.in_len())?;
+                let XvmCallArgs { vm_id, to, input } = env.read_as_unbounded(env.in_len())?;
 
-                // TODO: rethink this? How do we get valid env in chain extension? Need to know which data to encode.
-                // gas limit, taking into account used gas so far?
                 let _origin_address = env.ext().address().clone();
                 let _value = env.ext().value_transferred();
-                let _gas_limit = env.ext().gas_meter().gas_left();
                 let xvm_context = XvmContext {
                     id: vm_id,
+                    max_weight: remaining_weight,
                     env: None,
                 };
 
@@ -77,9 +70,14 @@ where
                     input,
                 );
 
-                // TODO: We need to know how much of gas was spent in the other call and update the gas meter!
-                // let consumed_xvm_weight = ...;
-                // env.charge_weight(consumed_xvm_weight)?;
+                // Adjust the actual weight used by the call if needed.
+                let actual_weight = match call_result {
+                    Ok(e) => e.actual_weight,
+                    Err(e) => e.post_info.actual_weight,
+                };
+                if let Some(actual_weight) = actual_weight {
+                    env.adjust_weight(charged_weight, actual_weight);
+                }
 
                 return match call_result {
                     Err(e) => {

chain-extensions/types/xvm/Cargo.toml

@@ -10,19 +10,15 @@ description = "Types definitions for contracts using xvm chain-extension."
 
 [dependencies]
 codec = { package = "parity-scale-codec", version = "3.0.0", default-features = false }
-frame-support = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.28", default-features = false }
+ink_prelude = { version = "3", default-features = false }
 scale-info = { version = "2.1.0", default-features = false, features = ["derive"] }
-sp-core = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.28", default-features = false }
 sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.28", default-features = false }
-sp-std = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.28", default-features = false }
 
 [features]
 default = ["std"]
 std = [
 	"codec/std",
-	"frame-support/std",
 	"scale-info/std",
-	"sp-core/std",
 	"sp-runtime/std",
-	"sp-std/std",
+	"ink_prelude/std",
 ]

chain-extensions/types/xvm/src/lib.rs

@@ -1,7 +1,8 @@
 #![cfg_attr(not(feature = "std"), no_std)]
+
 use codec::{Decode, Encode};
+use ink_prelude::vec::Vec;
 use sp_runtime::{DispatchError, ModuleError};
-use sp_std::vec::Vec; // TODO use ink_prelude::vec::Vec; ?
 
 #[cfg_attr(feature = "std", derive(scale_info::TypeInfo))]
 #[derive(PartialEq, Eq, Copy, Clone, Encode, Decode, Debug)]

contracts/xvm/Cargo.toml

@@ -9,20 +9,24 @@ repository = "https://github.com/AstarNetwork/astar-frame"
 description = "Chain extension for X-VM calls"
 
 [dependencies]
-ink_env = { version = "3", default-features = false }
-ink_lang = { version = "3", default-features = false }
-ink_metadata = { version = "3", default-features = false, features = ["derive"], optional = true }
-ink_prelude = { version = "3", default-features = false }
-ink_primitives = { version = "3", default-features = false }
-ink_storage = { version = "3", default-features = false }
+ink_env = { version = "3.3", default-features = false }
+ink_lang = { version = "3.3", default-features = false }
+ink_metadata = { version = "3.3", default-features = false, features = [
+	"derive",
+], optional = true }
+ink_prelude = { version = "3.3", default-features = false }
+ink_primitives = { version = "3.3", default-features = false }
+ink_storage = { version = "3.3", default-features = false }
 
-scale = { package = "parity-scale-codec", version = "3", default-features = false, features = ["derive"] }
-scale-info = { version = "2", default-features = false, features = ["derive"], optional = true }
-
-xvm-chain-extension-types = { path = "../../chain-extensions/types/xvm", default-features = false }
+scale = { package = "parity-scale-codec", version = "3", default-features = false, features = [
+	"derive",
+] }
+scale-info = { version = "2", default-features = false, features = [
+	"derive",
+], optional = true }
 
 [lib]
-name = "xvm_chain_extension_contract"
+name = "xvm_example"
 path = "src/lib.rs"
 crate-type = [
 	# Used for normal contract Wasm blobs.
@@ -36,6 +40,7 @@ std = [
 	"ink_env/std",
 	"ink_storage/std",
 	"ink_primitives/std",
+	"ink_prelude/std",
 	"scale/std",
 	"scale-info/std",
 ]

contracts/xvm/src/lib.rs

@@ -1,8 +1,22 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
-use ink_env::{DefaultEnvironment, Environment};
 use ink_lang as ink;
-use xvm_chain_extension_types::XvmCallArgs;
+
+use ink_env::{DefaultEnvironment, Environment};
+use ink_prelude::vec::Vec;
+
+#[derive(Clone, PartialEq, Eq, scale::Encode, scale::Decode, Debug)]
+pub struct XvmCallArgs {
+    /// virtual machine identifier
+    pub vm_id: u8,
+    /// Call destination (e.g. address)
+    pub to: Vec<u8>,
+    /// Encoded call params
+    pub input: Vec<u8>,
+}
+
+pub const FRONTIER_VM_ID: u8 = 0x0F;
+pub const PARITY_WASM_VM_ID: u8 = 0x1F;
 
 #[ink::chain_extension]
 pub trait XvmChainExtension {
@@ -53,7 +67,7 @@ impl Environment for CustomEnvironment {
 ///
 /// This will give us access to the chain extension that we've defined.
 #[ink::contract(env = crate::CustomEnvironment)]
-mod xvm_chain_extension_contract {
+mod xvm_example {
 
     use super::*;
     use scale::Encode;
@@ -72,10 +86,9 @@ mod xvm_chain_extension_contract {
             self.env()
                 .extension()
                 .xvm_call(XvmCallArgs {
-                    vm_id: xvm_chain_extension_types::FRONTIER_VM_ID,
-                    to: address.encode(), // TODO: is this correct?
+                    vm_id: FRONTIER_VM_ID,
+                    to: address.encode(),
                     input: Default::default(),
-                    metadata: Default::default(),
                 })
                 .map_err(|_| ExtensionError::XvmCallFailed)?;
 

frame/pallet-xvm/src/evm.rs

@@ -1,6 +1,7 @@
 //! EVM support for XVM pallet.
 
 use crate::*;
+use pallet_evm::GasWeightMapping;
 use sp_core::{H160, U256};
 use sp_runtime::traits::Get;
 
@@ -19,22 +20,22 @@ where
         I::get()
     }
 
-    fn xvm_call(
-        _context: XvmContext<VmId>,
-        from: T::AccountId,
-        to: Vec<u8>,
-        input: Vec<u8>,
-    ) -> Result<Vec<u8>, Vec<u8>> {
+    fn xvm_call(context: XvmContext, from: T::AccountId, to: Vec<u8>, input: Vec<u8>) -> XvmResult {
         log::trace!(
             target: "xvm::EVM::xvm_call",
-            "Start EVM XVM: {:?}, {:?}, {:?}, {:?}",
-            from, to, input, metadata,
+            "Start EVM XVM: {:?}, {:?}, {:?}",
+            from, to, input,
         );
         let value = U256::from(0u64);
         let max_fee_per_gas = U256::from(3450898690u64);
-        let gas_limit = 4000000u64;
-        let evm_to: H160 = Decode::decode(&mut to.as_ref())
-            .map_err(|_| b"`to` argument decode failure".to_vec())?;
+        let gas_limit = T::GasWeightMapping::weight_to_gas(context.max_weight);
+        log::trace!(
+            target: "xvm::EVM::xvm_call",
+            "EVM xvm call gas limit: {:?} or as weight: {:?}", gas_limit, context.max_weight);
+        let evm_to = Decode::decode(&mut to.as_ref()).map_err(|_| XvmCallError {
+            error: XvmError::EncodingFailure,
+            consumed_weight: PLACEHOLDER_WEIGHT,
+        })?;
 
         let res = pallet_evm::Pallet::<T>::call(
             frame_support::dispatch::RawOrigin::Root.into(),
@@ -47,14 +48,20 @@ where
             None,
             None,
             Vec::new(),
-        );
+        )
+        .map_err(|e| XvmCallError {
+            error: XvmError::ExecutionError(Vec::default()), // TODO: make error mapping make more sense
+            consumed_weight: e.post_info.actual_weight.unwrap_or(context.max_weight),
+        })?;
 
         log::trace!(
             target: "xvm::EVM::xvm_call",
             "EVM XVM call result: {:?}", res
         );
 
-        // TODO: return result or error if call failure
-        Ok(Default::default())
+        Ok(XvmCallOk {
+            output: Default::default(), // TODO: Fill output vec with response from the call
+            consumed_weight: res.actual_weight.unwrap_or(context.max_weight),
+        })
     }
 }