On 7/27/2025 5:20 AM, Michael Kelley wrote:
From: Naman Jain <namj...@linux.microsoft.com> Sent: Thursday, July 24, 2025
1:26 AM
Provide an interface for Virtual Machine Monitor like OpenVMM and its
use as OpenHCL paravisor to control VTL0 (Virtual trust Level).
Expose devices and support IOCTLs for features like VTL creation,
VTL0 memory management, context switch, making hypercalls,
mapping VTL0 address space to VTL2 userspace, getting new VMBus
messages and channel events in VTL2 etc.
Co-developed-by: Roman Kisel <rom...@linux.microsoft.com>
Signed-off-by: Roman Kisel <rom...@linux.microsoft.com>
Co-developed-by: Saurabh Sengar <ssen...@linux.microsoft.com>
Signed-off-by: Saurabh Sengar <ssen...@linux.microsoft.com>
Reviewed-by: Roman Kisel <rom...@linux.microsoft.com>
Reviewed-by: Alok Tiwari <alok.a.tiw...@oracle.com>
Message-ID: <20250512140432.2387503-3-namj...@linux.microsoft.com>
Reviewed-by: Saurabh Sengar <ssen...@linux.microsoft.com>
Reviewed-by: Nuno Das Neves <nunodasne...@linux.microsoft.com>
Signed-off-by: Naman Jain <namj...@linux.microsoft.com>
---
drivers/hv/Kconfig | 22 +
drivers/hv/Makefile | 7 +-
drivers/hv/mshv_vtl.h | 52 ++
drivers/hv/mshv_vtl_main.c | 1508 +++++++++++++++++++++++++++++++++++
include/hyperv/hvgdk_mini.h | 106 +++
include/uapi/linux/mshv.h | 80 ++
6 files changed, 1774 insertions(+), 1 deletion(-)
create mode 100644 drivers/hv/mshv_vtl.h
create mode 100644 drivers/hv/mshv_vtl_main.c
[snip]
+
+static int mshv_vtl_set_reg(struct hv_register_assoc *regs)
+{
+ u64 reg64;
+ enum hv_register_name gpr_name;
+ int i;
+
+ gpr_name = regs->name;
+ reg64 = regs->value.reg64;
+
+ /* Search for the register in the table */
+ for (i = 0; i < ARRAY_SIZE(reg_table); i++) {
+ if (reg_table[i].reg_name == gpr_name) {
+ if (reg_table[i].debug_reg_num != -1) {
+ /* Handle debug registers */
+ if (gpr_name == HV_X64_REGISTER_DR6 &&
+ !mshv_vsm_capabilities.dr6_shared)
+ goto hypercall;
+ native_set_debugreg(reg_table[i].debug_reg_num,
reg64);
+ } else {
+ /* Handle MSRs */
+ wrmsrl(reg_table[i].msr_addr, reg64);
+ }
+ return 0;
+ }
+ }
+
+hypercall:
+ return 1;
+}
+
+static int mshv_vtl_get_reg(struct hv_register_assoc *regs)
+{
+ u64 *reg64;
+ enum hv_register_name gpr_name;
+ int i;
+
+ gpr_name = regs->name;
+ reg64 = (u64 *)®s->value.reg64;
+
+ /* Search for the register in the table */
+ for (i = 0; i < ARRAY_SIZE(reg_table); i++) {
+ if (reg_table[i].reg_name == gpr_name) {
+ if (reg_table[i].debug_reg_num != -1) {
+ /* Handle debug registers */
+ if (gpr_name == HV_X64_REGISTER_DR6 &&
+ !mshv_vsm_capabilities.dr6_shared)
+ goto hypercall;
+ *reg64 =
native_get_debugreg(reg_table[i].debug_reg_num);
+ } else {
+ /* Handle MSRs */
+ rdmsrl(reg_table[i].msr_addr, *reg64);
+ }
+ return 0;
+ }
+ }
+
+hypercall:
+ return 1;
+}
+
One more comment on this patch. What do you think about
combining mshv_vtl_set_reg() and mshv_vtl_get_reg() into a single
function? The two functions have a lot code duplication that could be
avoided. Here's my untested version (not even compile tested):
+static int mshv_vtl_get_set_reg(struct hv_register_assoc *regs, bool set)
+{
+ u64 *reg64;
+ enum hv_register_name gpr_name;
+ int i;
+
+ gpr_name = regs->name;
+ reg64 = ®s->value.reg64;
+
+ /* Search for the register in the table */
+ for (i = 0; i < ARRAY_SIZE(reg_table); i++) {
+ if (reg_table[i].reg_name != gpr_name)
+ continue;
+ if (reg_table[i].debug_reg_num != -1) {
+ /* Handle debug registers */
+ if (gpr_name == HV_X64_REGISTER_DR6 &&
+ !mshv_vsm_capabilities.dr6_shared)
+ goto hypercall;
+ if (set)
+ native_set_debugreg(reg_table[i].debug_reg_num,
*reg64);
+ else
+ *reg64 =
native_get_debugreg(reg_table[i].debug_reg_num);
+ } else {
+ /* Handle MSRs */
+ if (set)
+ wrmsrl(reg_table[i].msr_addr, *reg64);
+ else
+ rdmsrl(reg_table[i].msr_addr, *reg64);
+ }
+ return 0;
+ }
+
+hypercall:
+ return 1;
+}
+
Two call sites would need to be updated to pass "true" and "false",
respectively, for the "set" parameter.
I changed the gpr_name matching to do "continue" on a mismatch
just to avoid a level of indentation. It's functionally the same as your
code.
Michael
Acked, looks good. Thanks for sharing the improvements. Sending v7 now.
Regards,
Naman
