Measure total server memory used by SQL Server:

SELECT cntr_value / 1024.0 AS TotalServerMemoryMB

FROM sys.dm_os_performance_counters

WHERE counter_name = 'Total Server Memory (KB)';

For physical (if VM host is stealing) and buffer use:

SELECT CAST(physical_memory_in_bytes / (1024.0 * 1024.0 * 1024.0) AS DECIMAL(20, 2)) AS PhysicalMemoryGB,

CAST((bpool_committed * 8) / (1024.0 * 1024.0) AS DECIMAL(20, 2)) AS BufferPoolCommittedMemoryGB

FROM sys.dm_os_sys_info;